In 1987, Mitchell Carlton Sims was convicted of the first degree murder of John Harrigan, a Domino’s Pizza employee who delivered a pizza to Sims and his girlfriend, Ruby Padgett, at their motel room in Glendale, and the attempted murders of two other Domino’s employees, Kory Spi-roff and Edward Sicam. He was sentenced to death. The California Supreme Court affirmed. People v. Sims, 5 Cal.4th 405, 20 Cal.Rptr.2d 537, 853 P.2d 992 (1993), cert. denied, Sims v. California, 512 U.S. 1253, 114 S.Ct. 2782, 129 L.Ed.2d 893 (1994). After the supreme court denied Sims’s petition for a writ of habeas corpus, Sims filed a 28 U.S.C. § 2254 petition in the United States District Court for the Central District of California on April 22, 1996. Following an evidentiary hearing, the district court denied all of Sims’s claims on May 2, 2003.
The Antiterrorism and Effective Death Penalty Act of 1996 (AEDPA) does not apply to the merits of Sims’s appeal because his federal petition was filed before AEDPA’s effective date, Lindh v. Murphy, 521 U.S. 320, 327, 117 S.Ct. 2059, 138 L.Ed.2d 481 (1997), but it does apply to the procedures for seeking review. Accordingly, Sims obtained a Certificate of Appealability (COA) on seven issues: (1) whether his rights under Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966), were violated by the admission of confessions obtained in a custodial setting after he invoked his rights to counsel and silence; (2) whether the prosecutor’s peremptory challenges to two Hispanic prospective jurors violated Batson v. Kentucky, 476 U.S. 79, 106 S.Ct. 1712, 90 L.Ed.2d 69 (1986); (3) whether his right to an impartial jury was violated when a member of his jury met with a member of Padgett’s jury and discussed writing a book about their experiences; (4) whether his Eighth and Fourteenth Amendment rights were violated by the prosecutor’s closing argument in the penalty phase about factor (k), the last factor in mitigation under California law that covers “any other circumstance which extenuates the gravity of the crime”; (5) whether trial counsel rendered ineffective assistance during the penalty phase by failing to investigate, develop, and present mitigating *563evidence about Sims’s mental condition; (6) whether counsel was ineffective in failing to object to comments that Sims argues violated Griffin v. California, 380 U.S. 609, 85 S.Ct. 1229, 14 L.Ed.2d 106 (1965); and (7) whether reversal is required on account of cumulative error.
We affirm.
I
A
Sims had managed a Domino’s Pizza parlor in West Columbia, South Carolina before resigning when he got angry at his boss for withholding part of a bonus.1 Sims sought revenge, and told his then-girlfriend that he wanted to use explosives to kill the boss. He bought a gun. On November 15, 1985, Sims was hired ás a delivery driver by another Domino’s, in Hanahan, South Carolina.
On December 8, 1985, Sims and Padgett ended up in Glendale, California. They went to a Domino’s and asked Kory Spi-roff, the assistant manager, for directions to, a drugstore. On the afternoon of the next day, a man and- woman went to a Sears store in Glendale and bought a package of socks, underwear, a clothesline, and a knife. The sales clerk overheard the woman tell the man to relax because they would be leaving the store shortly.
On the evening of December 9, Spiroff was on duty with delivery drivers Edward Sicam and John Harrigan.- Each had on a Domino’s uniform, consisting of short-sleeved shirts with a Domino’s badge and name tag. At 11:03 p.m., Brian Scarlett, an off-duty Domino’s employee who was visiting .Spiroff, took a telephone order from a man with a southern accent. The caller asked for the pizza to be delivered to Room 205 of the Regalodge Motel. The motel was a three-minute drive from the parlor. Harrigan, who was twenty-one years old, left the parlor at 11:26 p.m. in his Toyota truck to make the delivery.
Around 11:45 p.m., Sims and Padgett went into the Domino’s. Spiroff recognized the couple from the day before. This time, Sims pointed a gun at Sicam and ordered Spiroff and Sicam into a back office. When Spiroff warned Sims that a delivery driver was due back at any moment, Sims took off his sweater to reveal a Domino’s shirt with Harrigan’s name tag and chuckled, “No, I don’t think so.”
Sims found a bank deposit bag which he gave to Padgett, who then emptied the parlor’s cash drawers. Sims told her to watch for fingerprints, and she began wiping the tables and cash drawers at his direction. Sims ordered Spiroff and Sicam to stand in the corner of the office and aimed his gun directly at them.
At this point, Richard Wagner, an off-duty Domino’s employee, arrived at the parlor with his wife. Sims told Spiroff to go to the front counter, threatening to shoot Sicam unless Spiroff cooperated. Instead of acknowledging Wagner as a friend, Spiroff asked him for his order. Meanwhile, Sims took an order over the phone, identifying himself as “Mitch” to the customer. While Spiroff prepared the pizzas, Sims, told the Wagners to wait in the car .for their pizza to be brought to them. After Sims gave the Wagners their pizza, they drove off and, suspecting a burglary, called the police.
Sims decided to take Spiroff and Sicam, one at a time, into the walk-in cooler. The cooler was 8 feet by 12 feet, with a 3-tier *564rack against the left wall. The temperature was kept at 32 to 40 degrees. Sims tied Spiroff s hands tightly behind his back with one end of a rope, looped the other end over the rack, and lifted Spiroff s arms painfully high by pulling down on the rope. This forced Spiroff to stand on his tiptoes to ease the tension in the rope and alleviate the pain. When Spiroff complained, Sims replied, “Shut up. At least you live.” Next, Sims wrapped the end of the rope around Spiroff s neck and tied it so tightly with a knot in back of the neck that Spiroff would strangle if he stopped standing on his tiptoes. Sims asked Spiroff when the cooler would be opened the following day. Spiroff said at 11 a.m. Sims replied that, by then, he and Padgett would be in San Francisco. When Spiroff asked Sims about Harrigan, Sims said that Harrigan had been tied up at the motel and would be found after Spiroff was found.
Sims then brought Sicam into the cooler and bound him in the same manner as Spiroff. When Sicam said he was choking, Sims responded, “You are alive.” Sims closed the cooler and left at 12:15 a.m. with Padgett.
While standing on the toes of one foot, Spiroff tried to knock over cartons so they could stand on them and relieve some of the pressure around the neck, but the rope tightened as he moved. Eventually he succeeded in knocking a box over. Nevertheless, at some point Spiroff blacked out.
Responding to Wagner’s call, Glendale police officers arrived at 12:30 a.m. They found Spiroff and Sicam in the cooler. One of them told the officers that their assailant was wearing Harrigan’s shirt and that Harrigan had not returned from delivering a pizza to the Regalodge.
The officers went to the Regalodge, got the key and registration card to room 205, which was registered to Sims, and found Harrigan’s dead body in the bathtub. The bathtub was full of water, and Harrigan’s body was submerged under the water on his right side with his back parallel to the side of the tub. Cold water was running at full blast onto the back of Harrigan’s neck. His head was immediately under the spout, about one inch below the water line. The drain plug was broken, but the tub was filled with water up to the overflow valve. Harrigan’s wrists were bound behind his back; his ankles were bound; and his feet and hands were “hogtied” together behind his back. His head was covered with a pillow case, which was secured with a rope ligature around the neck. A washcloth had been placed inside his mouth, held in place by a sock tied around his head.
Dr. Joseph Cogan, the state’s forensic pathologist, who performed the autopsy on Harrigan’s body, determined that the cause of death was ligature strangulation based on the depth of the furrow around the decedent’s neck, indicating the extreme pressure of the ligature around the neck, and hemorrhages on the inner eyelids, indicating that Harrigan was alive when the neck ligature was applied because it obstructed blood flow to the head and brain. Cogan opined that Harrigan lived for no more than ten minutes after the neck ligature was applied and that the ligature in itself was enough to kill Harri-gan. However, Cogan could not rule out the possibility that drowning contributed to Harrigan’s death, based upon Harri-gan’s having been found fully submerged in a bathtub of water with a gag in his mouth, and the presence of frothy pulmonary edema in his trachea and bronchi.
No money, wallet, or car keys belonging to Harrigan were found in the room. The phone lines had been cut. Although the room had been wiped clean with a wet towel, Sims’s fingerprints were found inside a toilet paper roll and in a telephone *565book on the page listing “pizza.” The knots used to tie up the ligatures on Harri-gan’s neck were identical to those used to tie up-Spiroff and Sicam. The rope used to bind Harrigan, Spiroff, and Sicam was similar to the clothes line sold to the young couple at the Glendale Sears the day before Harrigan’s murder.
Sims and Padgett were apprehended in a Las Vegas motel on December 25 by the Las Vegas police acting on an anonymous tip. A fully loaded '.25 caliber pistol was found under the mattress. The police also recovered a Los Angeles Times article entitled, “Delivery Man Slain While Making Run,” and a yellow page torn from a Las Vegas telephone book listing Domino’s Pizza establishments. Harrigan’s pickup truck, with a Domino’s shirt bearing Har-rigan’s name tag inside, was also found in Las Vegas about twenty miles from the motel.
Sims was taken to the Clark County jail. Officers Jonathan Perkins and Gary Mon-teeuollo of the Glendale Police Department met with him in an interview room. Informed of his rights pursuant to Miranda, Sims acknowledged his understanding and signed a written form indicating that he did not waive his rights. As Perkins gathered his papers and stood up to leave, Sims asked what was going to happen to him from that point on, and indicated that he would like to go to South Carolina rather than California. During the conversation that followed, Sims told Perkins, “I had to kill that boy” and “He would have identified me.” At the end' of the interview, Perkins told Sims that Sims would have to initiate any further conversation about the investigation, which Sims did the next day. Perkins tape recorded this interview, which included Sims’s statement “I just got drunk, and I didn’t know what the fuck I was ... I knew I was doing it, but I shouldn’t have done it.” After Perkins readvised Sims of his Miranda rights, Sims said that he had worked for Domino’s Pizza in South Carolina and that he and Padgett had traveled by bus from that state to Glendale where they rented room 205 at the Regalodge. He told Perkins they had gone to Domino’s for directions to a drugstore, and to Sears to buy a knife. He said that the next day they returned to Domino’s for a pizza. At that point Sims ended the interview.
Sims’s December 25 statements and an edited version of the tape of the December 26 interview were admitted in the guilt phase.
Sims did not testify. His forensic pathologist, Dr. Robert Bucklin, testified that the white, frothy material in Harri-gan’s larynx and trachea indicated that he had drowned, and that the furrow and hemorrhages could have resulted from the posture of Harrigan’s head rather than asphyxia. Bucklin also testified that strangulation might have contributed to Harri-gan’s death. Stephen Schliebe, a private criminalist, testified that a piece of rope tied as the ligature was to Harrigan’s neck would not cause loss of consciousness. Sims’s theory of defense was that Harri-gan was alive when Sims put him in the bathtub and left with Padgett, and that he lacked the intent to kill Harrigan, Spiroff, or Sicam.
The jury found Sims guilty of one count of first degree murder, with two special circumstances findings (that Sims committed the murder while lying in wait and during the commission of a robbery), two counts of attempted murder, and three counts of robbery. The jury also found that Sims used a firearm during the commission of each offense.
B
At the penalty phase the prosecution introduced evidence that Sims robbed and *566shot to death two Domino’s Pizza employees in Hanahan, South Carolina less than one week before the Glendale crimes. Just after 2 a.m. on December 4, approximately two weeks after Sims was hired as a delivery driver at the Hanahan Domino’s, Gary Melkie, the assistant manager, appeared in the lobby of the Police Department about three blocks away, dressed in his uniform with a telephone cord dangling from one of his wrists and bleeding profusely from gunshot wounds to his head and neck. A paramedic responded and Melkie was placed in an ambulance. En route to the hospital, the ambulance detoured to the parlor where another shooting had been reported. There, the police had found Chris Zerr, a delivery driver, lying on the floor covered with blood, his hands tied behind his back with a telephone cord. He died shortly thereafter from a gunshot wound to the head. $1,164 had been taken from the cash drawers.
At the hospital, the paramedic asked Melkie who had shot him and Melkie responded, “Sims. Mitch Sims.” Melkie said that Sims had tied him up and then shot Zerr. Melkie repeated the same thing to a police officer, including a description of Sims, and said that Sims worked for Domino’s. Melkie died after surgery.2
Melkie had suffered four gunshot wounds to the head and neck, a bullet casing was removed from his tongue, and a fifth bullet, which had exited from his head, was recovered from a wall at the parlor.
An unedited version of the tape recording of Sims’s December 26 statement to Perkins was admitted into evidence and played for the jury. In that portion of the statement, Sims recounted that he had robbed a Domino’s Pizza parlor in South Carolina before going to California.
The defense presented as mitigating evidence a number of witnesses who testified about Sims’s brutal family background of physical, sexual, and emotional abuse. His mother, Mildred, testified that Sims only saw his natural father (from whom she was divorced) on two or three occasions during his childhood, and that she married Arnold Cranford in 1961. She had three children with her first husband and two with Cran-ford. Cranford had a drinking problem and became violent and sexually abusive when intoxicated. She testified that Cran-ford raped Sims when he was seven years old, and forced Sims to engage in oral sex with him over the years. When Sims was sixteen, Cranford made him have sexual intercourse with his mother. They both cried during the incident. On another occasion, Cranford forced Sims to have intercourse with his older sister Merlon. Cran-ford repeatedly told Sims that Sims was “no good” and a bad person. Sims began drinking heavily at fourteen, and attempted suicide by drowning when he was an adolescent.
Merlon testified to repeated incidents of physical and sexual abuse that she and the other children suffered at the hands of Cranford. She said that every night was a nightmare, and that “[i]t ain’t never going to leave me alone.” Cranford would drag her out of bed, force her to strip, and then beat her, tie her to a bed, fondle her, and occasionally have sexual intercourse with her. Cranford brought men home and forced her to have sex with them. She also attempted suicide several times. *567Cranford threatened to kill the children if they told anyone about what he did. When Sims was sixteen, Cranford forced Sims’s younger stepsister, Margaret, to undress and lie beside him in bed. He began to fondle her and told her he was going to have sex with her, but Sims called the police. Cranford was arrested and convicted.
Sims’s brother Eddie also testified. He watched as Cranford forced Sims to have sex with Cranford on many occasions. He heard Cranford having sex with Margaret in the next room. Eddie also tried to commit suicide, and he said that Sims tried to lift up his spirits. Sims’s other siblings did not testify, but there was evidence that Margaret ran away from home and began taking drugs, and that his brother Jimmy was a career army officer.
Sims’s wife, Theresa, had known Sims since she was nine, and she, too, had experienced an abusive childhood. They were married when Sims was twenty and she was sixteen. They had three children, who worship Sims and live for his phone calls and letters. She testified about various jobs that Sims had held, and said that he became withdrawn and depressed whenever he was promoted at work, that he engaged in extensive substance abuse, and that he suffered a sense of worthlessness and guilt from the incestuous act he committed with his mother. While he was working at Domino’s, Sims had an affair with a co-worker but came back to Theresa. He left Theresa again when he met Padgett. Sims told Theresa he was no good for her and did not want to pull her, and the boys, down with him. At her urging, he saw a counselor and cried as he recounted the abuse he had suffered. Sims’s mother, sister and stepbrother, as well as his wife, testified that Sims was sensitive and continued to be a good, supportive father to his three children.
Dr. William Vicary, a psychiatrist, testified that Sims suffered from chronic depression, and alcohol and drug abuse. He stated that Sims had long-standing feelings of inadequacy,' low self-esteem, despair, shame, and humiliation. Vicary explained that individuals who have suffered a lot of verbal and physical abuse tend to be crippled from a psychological point of view and have trouble later in life, becoming violent, abusive adults. On cross-examination Vicary admitted that Sims had never been diagnosed as mentally ill, and that his depression was not severe.
At the conclusion of the penalty phase, the jury fixed the punishment at death.
C
Sims appealed to the California Supreme Court, which upheld both the conviction and sentence. Sims, 5 Cal.4th at 467, 20 Cal.Rptr.2d 537, 853 P.2d 992. With respect to the issues that are now before us, it concluded that the prosecutor based his juror challenges on his perception of an individual bias, not on the basis of group bias; that admission of Sims’s confessional statements on December 25 and 26 was harmless error under Chapman v. California, 386 U.S. 18, 87 S.Ct. 824, 17 L.Ed.2d 705 (1967), given overwhelming evidence of Sims’s intent to kill Harrigan independent of those statements; 3 and that there was no reasonable possibility the jury was misled to believe it could not consider Sims’s background in mitigation. The United States Supreme Court denied Sims’s petition for writ of certiorari. Clark v. California, 512 U.S. *5681253, 114 S.Ct. 2783, 129 L.Ed.2d 894 (1994). Sims filed a state habeas petition in February 1993, which was summarily denied on March 2, 1994.
Sims initiated federal proceedings by filing a request for stay of execution and appointment of counsel on August 8, 1995. His petition for habeas relief was filed on April 22, 1996. The district court found some claims unexhausted and granted Sims leave to amend his petition to delete those claims. Sims filed a second petition in state court on October 10, 1997, which the California Supreme Court denied on April 29, 1998. After he amended his federal petition, Sims asked for an evidentiary hearing and was given a hearing on one of the claims that is pursued on appeal— ineffective assistance of counsel regarding mental health evidence. On this claim the district court found that* Sims failed to establish that his attorney’s performance was deficient because counsel consulted qualified experts who did not suggest the need for additional information or experts after being informed of the relevant information about Sims’s background and relationships. On other claims raised on appeal, the court held in an exhaustive order that Sims’s claim of juror misconduct was not supported by any indication that there were improper communications between the Sims juror and the Padgett juror. With respect to Sims’s admissions, the district court agreed with the trial court (rather than with the California Supreme Court) that the statement “I had to kill that boy” was not made in response to interrogation; it held that Sims’s statement “The boy
would have identified me” was the product of remarks by Perkins that the officer should have known were reasonably likely to elicit an incriminating response; and it concluded that Sims’s December 26 statement that “I just got drunk, and I didn’t know what the fuck I was ... I knew what I was doing, but I shouldn’t have done it” was a response to express questioning about the crime itself by Perkins that should not have been admitted, but that his post-Miranda statements were properly admitted. Regardless, applying Brecht harmless error analysis,4 the district court embraced the California Supreme Court’s finding (applying the stricter Chapman standard) that even if a portion of Sims’s statements were admitted erroneously, any error was harmless. The court rejected Sims’s challenge to the prosecutor’s argument about mitigating evidence because, in its opinion, the prosecutor never told the jury to disregard Sims’s history of abuse but instead argued that it lacked weight and, even if the argument were improper, any error was cured by the trial court’s instructions. With respect to Sims’s Batson claim, the district court held that Sims failed to show purposeful discrimination given the prosecutor’s explanation that his challenges were based on the jurors’ lack of life experience and responsibility. Finally, the court saw no ineffectiveness in counsel’s failure to object to the prosecutor’s comment on Sims’s failure to testify as the prosecutor’s comments were not improper.
Sims has timely appealed the denial of his habeas petition.5
*569II
Sims argues that the incriminating statements he made to police officers on December 25 and 26 while he was in their custody and after he had invoked his right to counsel were obtained, and introduced, in violation of his Fifth and Fourteenth Amendment rights under Miranda and its progeny.6
After Sims had declined to waive his rights on the 25th, and Perkins had started to leave, Sims asked what was going to happen to him from that point on, and said that he would rather go to South Carolina than California. Perkins replied that he planned to obtain Sims’s extradition to California, that there were warrants for Sims’s arrest in connection with the murder of two Domino’s employees in South Carolina as well as for the murder in Glendale, that he was investigating the Glendale murder, and that the body of a Domino’s delivery driver was discovered in' room 205 of the Regalodge where he had reason to believe that Sims and a young woman were staying. Sims interjected, “I had to kill that boy.” Perkins responded, “What did you say?” and Sims repeated, “I had to kill that boy.” Perkins then described how Harrigan’s body was found, and commented that Harrigan “did not have to die in this manner and could have been left there tied and gagged in the manner in which he was found.” Sims stated “The boy would have identified me.” As he was leaving, Perkins told Sims that he would have to initiate further conversation about the investigation. The next day Sims asked to see the Glendale officers.
Perkins took a tape recorder with him on the 26th. Sims complained about being in the “hole” because jail authorities thought he was going to kill himself. Perkins asked whether he was going to and Sims said “Why should I?” Perkins said, “O.K., that’s all I want to hear ... You don’t seem like that kind of guy.” Sims responded: “I’m not, I’m not a murderer either but,.... ” Perkins said: “What does that mean?” And Sims answered: “That means that I just got drunk, and I didn’t *570know what the fuck I was, I knew I was doing it, but I shouldn’t of done it.” Perkins told Sims he had trouble discussing the case because Sims had not waived his Miranda rights. Sims expressed interest in returning to South Carolina where his family was, and remaining in the same state as Padgett. Perkins explained that Sims would likely be tried first in California, then be released to South Carolina, when Sims said: “You know they won’t even let me see a lawyer, they have charges against me in Nevada, huh ..., lawyer.” Perkins said: “You’re a fugitive, yeah. Well tomorrow, you go to court.” Sims asked: “Why don’t they charge me with possession of pot or something? (Laughs.) I had a bag.”
Later, Perkins readvised Sims of his Miranda rights, and Sims waived them to discuss Padgett’s lack of involvement in the South Carolina crimes. Sims said that he had worked at a Domino’s Pizza in Columbia for thirteen months before moving to Charleston. He admitted robbing a Domino’s in a Charleston suburb, but told the officers that Padgett was unaware of the robbery until after it happened. The next morning they left for Jacksonville, Florida, and from there went to Los Ange-les. Sims said he and Padgett rented room 205 at the Glendale Regalodge on December 8. He told Perkins they had gone to Domino’s for directions to a drugstore, and to Sears to buy a knife. He said that the next day they returned to Domino’s for a pizza. At that point Sims ended the interview.
A
Sims contends that the California Supreme Court correctly held that he unambiguously invoked his right to counsel on December 25; that for this reason all interrogation had to stop; and that he did not re-initiate discussion about the Glendale murder either by asking about extradition on the 25th, because that question concerned the routine incidents of the custodial relationship instead of the criminal investigation, or by contacting the Glendale officers on the 26th. The state counters that the trial court and the district court correctly determined that Sims’s initial incriminating statement “I had to kill that boy” was spontaneous and not in response to interrogation, and that the trial court’s findings with respect to the remaining comments were correct. This is a debate that we need not engage, however, because we agree with both the California Supreme Court and the district court that admitting Sims’s incriminating remarks was harmless.7
We “review the evidence at trial to determine whether the confession likely had a substantial and injurious impact on the verdict; if not, its admission was harmless.” Taylor v. Maddox, 366 F.3d 992, 1016 (9th Cir.2004) (citing Brecht v. Abrahamson, 507 U.S. 619, 637-39, 113 S.Ct. 1710, 123 L.Ed.2d 353 (1993)). “If a habe-as court is left with ‘grave doubt’ about whether a constitutional error substantially influenced the verdict, then the error was not harmless.” Parle v. Runnels, 387 F.3d 1030, 1044 (9th Cir.2004) (citing O’Neal v. McAninch, 513 U.S. 432, 438, 115 S.Ct. 992, 130 L.Ed.2d 947 (1995)).
Sims suggests that both courts conducted their harmless error analysis — the California Supreme Court under Chapman, and the district court under Brecht — improperly by assessing the strength of the state’s evidence apart from the erroneous*571ly admitted statements. We do not think so, because courts do review all the state’s evidence to determine whether error had a substantial and injurious effect on the jury’s verdict. See, e.g., Brecht, 507 U.S. at 639, 113 S.Ct. 1710 (finding harmless error in part because “the State’s evidence of guilt was, if not overwhelming, certainly weighty”); Parle, 387 F.3d at 1044 (concluding that error was harmless where “the prosecution had overwhelming evidence” of intent); see also Arizona v. Fulminante, 499 U.S. 279, 310, 111 S.Ct. 1246, 113 L.Ed.2d 302 (1991) (noting, under the Chapman standard, that “[wjhen reviewing the erroneous admission of an. involuntary confession, the appellate court ... simply reviews the remainder of the evidence against the defendant to determine whether the admission of the confession was harmless beyond a reasonable doubt”). In any event, as we explain, the evidence of Sims’s guilt was overwhelming and there is no reasonable likelihood that the challenged statements actually prejudiced him.
At trial on the guilt phase, Sims’s only argument was that he did not intend to kill Harrigan, and thus the prosecution could not establish either first degree murder or the special circumstance of lying in wait. His theory was that Harrigan could have drowned himself, after Sims left, by turning onto his side and thereby submerging his head under water. However, as the California Supreme Court found, Harrigan “had been hog-tied and gagged, with a pillowcase pulled over his head and secured by a ligature bound so tightly that the victim inevitably would die of strangulation if death did not occur first by drowning — the victim having been left in the bathtub with the water running over his head.” Sims, 5 Cal.4th at 448, 20 Cal.Rptr.2d 537, 853 P.2d 992. In light of the record as a whole, it is clear that Sims’s incriminating statements did not have a substantial and injurious effect on the verdict.
Sims had it in for Domino’s, wanted revenge, and had expressed the desire to blow up a Domino’s pizza parlor with employees inside it. As a former Domino’s manager Sims knew how Domino’s operated. He had scouted out the Glendale Domino’s the day before, so he knew how long it would take the delivery driver to get to the motel and for Padgett and him to get from the motel to the parlor. Sims lured the delivery driver to Room 205 by calling to order a pizza at 11:03 p.m. Sometime after that he cut the phone cord. Harrigan left the parlor at 11:26 to deliver Sims’s pizza. Within less than twenty minutes, Harrigan had made the delivery, and Sims had stuffed a washcloth in Harri-gan’s mouth and tied it with a sock around his head; put a pillow case over Harrigan’s head, and tied it with a rope knotted in back of the neck tightly enough to strangle him; taken off Harrigan’s Domino’s shirt; tied Harrigan’s wrists together and tied his feet together, then hog-tied his hands and feet behind his back; stolen Harri-gan’s keys and money; put Harrigan into the bathtub with cold water running at full blast, which was unnecessary if Sims’s only aim were to incapacitate; and gone with Padgett to the parlor, arriving there (wearing Harrigan’s shirt underneath a sweater) before the delivery driver’s absence would be noticed. Room 205 was meticulously wiped clean of fingerprints, also a largely unnecessary precaution if Harrigan were meant to survive because he would be able to identify both of them.
Once at the parlor, Sims responded to Spiroff s warning that Harrigan would be returning from a delivery by chuckling, “No, I don’t think so,” and removing his sweater to reveal a Domino’s shirt with Harrigan’s name tag. Sims then proceeded to order Spiroff and Sicam into the *572corner of the office where he pointed his gun directly at them before being interrupted by Wagner’s arrival, and after taking care of Wagner’s order, bound the two employees in the cooler in such a way that they, too, would almost certainly die before the cooler was opened the following day. When Spiroff and Sicam complained, Sims responded “Shut up. At least you live.”
Although the prosecutor did rely on Sims’s statements in closing argument, the emphasis was on the “extremely life-endangering” way that Sims’s victims were bound, his calculated and expeditious execution of the crimes, his threats to blow up the South Carolina Domino’s, his meticulous wiping down of the motel room, and his apparent intention to kill Spiroff and Sicam. The prosecutor’s main point was that Sims guaranteed Harrigan would die in one of two ways: either he would be strangled to death by the ligature around his neck, or he would drown to death in the bathtub.
In sum, there was strong evidence of motive to kill, other circumstantial evidence that reflected careful planning to make sure Harrigan would not be missed or return, and evidence that pointed to death as the only possible outcome of putting a hog-tied person with a ligature around his neck in a bathtub with the water running. Accordingly, we conclude that although confessions are undoubtedly powerful evidence, Fulminante, 499 U.S. at 296, 111 S.Ct. 1246, apart from Sims’s statements, the evidence overwhelmingly showed that he meant for Harrigan to die, one way or the other.
B
Sims also argues that the prosecutor’s reliance on his statements at the penalty phase had a substantial and injurious effect in determining his sentence. First, he asserts that the prosecutor used Sims’s statements to argue that Harrigan’s killing was “vicious, sadistic, cruel, and needless.” In addition, he contends that the prosecutor’s reliance on the South Carolina crimes, which Sims partially described in his December 26 statements, to establish his planning, intent to kill, and lack of remorse “surely affected” the jury’s sentencing deliberations.8
To show that Sims deserved the death penalty, the prosecution predominantly relied on the depraved way in which Sims perpetrated his series of killings and attempted killings. Sims began in South Carolina, where he killed his coworkers, Zerr and Melkie. After Zerr was rendered helpless with his hands tied behind his back, Sims shot him to death at point blank range in the head. He proceeded to shoot Melkie, also bound, in the head, through the mouth (knocking out several teeth), in the back of the head, and through the neck, as Melkie moved around the room. After traveling to Glendale, Sims lured Harrigan, an innocent pizza delivery man, to his motel room, hogtied and gagged him, and, despite his incapacitation, then placed him in a bathtub with the water running full force. Having just killed three people in the last few days, Sims then drove to Domino’s in Harrigan’s uniform, chuckled as he told Spiroff and Sicam that Harrigan would not be returning, pointed a gun at Spiroff and Si-*573cam in the corner of the office before Wagner’s entrance, and laughed and joked with people in the store as he took pizza orders at the front counter. Before leaving, he hanged Spiroff and Sicam in the cooler in a manner that promised a slow, agonizing, and painful death. When he was arrested a couple of weeks later in a Las Vegas motel room, the police found a yellow page torn from a Las Vegas telephone book listing Domino’s Pizza establishments.
During the prosecutor’s discussion of the manner of Harrigan’s death in his closing argument, he suggested that Har-rigan had raised his head above the waterline in the bathtub to avoid drowning, leaving Sims to push his head back under the water. The prosecutor then made a passing reference to Sims’s statement, “I had to kill that boy.” He continued, “What more could Mitchell Sims do to John Har-rigan other than to take this helpless individual who was hogtied, bound, gagged, and strangled and hold his head under water until he stopped moving. It is as vicious, it is as sadistic, it is as cruel, it is as needless, absolutely needless a death as you can think.” Thus, the reference to Sims’s statement added nothing to the prosecutor’s point — that the circumstances of Harrigan’s death were especially heinous.
Sims also notes that the prosecutor relied on Sims’s South Carolina crimes, which Sims partially described in his December 26 statement. However, Sims’s statement could not have had any prejudicial effect because the entire story of how Sims shot and killed Melkie and Kerr was independently presented to the jury in the penalty phase.
Ill
During jury selection, the prosecutor used eight of his first twelve peremptory challenges to strike four African-American and four Hispanic venire panelists. These strikes left no black and one Hispanic-surnamed individual in the box. Sims argues that this statistical disparity, combined with other evidence, shows that two of the strikes — against Rolando Man-dujano and Maria Cerda — were exercised on the basis of race in violation of Batson v. Kentucky, 476 U.S. 79, 106 S.Ct. 1712, 90 L.Ed.2d 69 (1986).
Defense counsel raised a Wheeler objection after the prosecutor had challenged four prospective jurors who were black.9 The prosecutor offered individualized justifications for each strike, primarily having to do with the jurors’ views of the death penalty and reasonable doubt. One juror, Torey Gaines, the prosecutor believed was “too young” and he wanted people who were accustomed to exercising responsibility. The prosecutor also said: “There are several black jurors, I think, that are outstanding in this case that just haven’t been called. There are no Blacks. The only Black person in this case is the people’s expert witness. We have a southern white defendant and we have white victims. Why would I not want Blacks on the jury? As a matter of fact, I do want Blacks on the jury.” When counsel objected to peremptory challenges of Sonia Vasconcellos, Alfredo Estevez, Mandujano and Cerda, *574the prosecutor also volunteered an explanation for his strikes. Vasconcellos had a language problem and the prosecutor had problems communicating with her; Este-vez was very hostile to the death penalty; Mandujano was a “sharp guy” but was “a college student” who did not have the “life experiences” nor did he “exercise the kinds of responsibility needed in a case like this”; and Cerda was “[v]ery young” and did not “have the type of life experiences or responsibility to take on a case like this.” The prosecutor remarked that “[t]here are many Latins in the audience who I hope are called as jurors in this case. The defendant in this case is white. All the witnesses are white. There is one exception, a black expert that the people called, and there is a — at least one Latino that the people are going to call.” He added that he applied neutral criteria, likes minority jurors, and preferred “on a case like this to have minority jurors. I just haven’t gotten lucky yet.”
The trial judge found “some reason for the prosecution’s actions” with respect to six of those struck, including Mandujano, who “appeared quite young to the court,” but made no specific finding on Cerda. He denied the Wheeler motion, finding that “[tjhere is no evidence other than the fact that all four Black jurors have been peremptorily excused to support a finding at this time by the court of a systematic exclusion of Blacks or Hispanics.”
The California Supreme Court found that “the prosecutor’s stated justifications were facially race-neutral, based upon a perception of a ‘specific’ or individual bias of each juror rather than a group bias, and thus afforded a constitutionally permissible basis for the exercise of the peremptory challenges in question.” Sims, 5 Cal.4th at 430, 20 Cal.Rptr.2d 537, 853 P.2d 992. It also found that the voir dire of Cerda supported the prosecutor’s justifications as she “gave tentative, uncertain, and equivocal responses to nearly every question that was asked relating to the death penalty.” Id. at 431, 20 Cal.Rptr.2d 537, 853 P.2d 992. Finally, addressing Sims’s contention that the age of Manduja-no, Cerda and Gaines did not justify their excusal because the prosecution did not challenge two young Caucasian jurors (Karlberg and Blakely), the court found that “the full explanation given by the prosecutor for his challenges of the three jurors [was] not their numerical age but rather their apparent immaturity and inexperience with assuming weighty decisions and responsibilities. Additionally, the prosecutor did challenge one prospective Caucasian juror because of her youth.” Id. at 431, 20 Cal.Rptr.2d 537, 853 P.2d 992. The district court recognized that the trial court’s ruling that it was necessary to show a “systematic exclusion” of prospective jurors was incorrect, as the Constitution forbids striking a single juror for a discriminatory purpose, but agreed that the prosecutor gave race-neutral reasons for excluding jurors.
Batson involves a familiar three-step analysis:
First, the defendant must make out a prima facie case by showing that the totality of the relevant facts gives rise to an inference of discriminatory purpose. Second, once the defendant has made out a prima facie case, the burden shifts to the State to explain adequately the racial exclusion by offering permissible race-neutral justifications for the strikes. Third, if a race-neutral explanation is tendered, the trial court must then decide ... whether the opponent of the strike has proved purposeful racial discrimination.
Johnson v. California, — U.S.-,-, 125 S.Ct. 2410, 2416, 162 L.Ed.2d 129 (2005) (internal quotations and citations *575omitted). Here, there is no issue about the first step, as the trial court had no occasion to rule on whether a prima facie case had been made out because the prosecutor moved directly to step two. In these circumstances, “the preliminary issue of whether the defendant had made a prima facie showing becomes moot.” Hernandez v. New York, 500 U.S. 352, 359, 111 S.Ct. 1859, 114 L.Ed.2d 395 (1991).
Nor is there much of an issue about the second step. Sims acknowledges that the prosecutor’s 'explanation does not need to be persuasive, and argues only that it apparently proceeded from stereotypical assumptions about how jurors of particular races might react in a case like this. However, the prosecutor’s" proffered reasons for striking Mandujano and Cerda, which centered on their lack of responsibility, were race neutral.
With respect to the third step, Sims first contends that the California Supreme Court did not cure the trial court’s incorrect articulation of the legal standard. Even under de novo review, however, we conclude that the record demonstrates that there was no Batson error.
Sims argues that the pretextual nature of the prosecutor’s explanations is manifest in the racially disparate pattern of his peremptory challenges, his explicit race-based strategy, and a comparative analysis of the struck jurors with empaneled jurors. Although discriminatory intent may be inferred from the fact that the prosecutor exercised four of his first twelve peremptory challenges to strike jurors with Hispanic surnames, see Hernandez, 500 U.S. at 363, 111 S.Ct. 1859, at least one Híspame-surnamed member of the venire was empaneled. This might indicate that the prosecutor’s motive "was non-discriminatory. See Turner v. Marshall, 121 F.3d 1248, 1254 (9th Cir.1997). As we have already discussed, the prosecutor commented that he had no reason to strike minority jurors, and in fact had a black and Hispanic witness. See Hernandez, 500 U.S. at 370, 111 S.Ct. 1859 (noting that the ethnicity of victims and prosecution witnesses could be taken as evidence of the prosecutor’s sincerity).
Finally, the prosecutor explained that he struck Cerda and Mandujano because he doubted their capacity to exercise the responsibility of jurors in a capital case. The Supreme Court recently made clear that “[i]f a prosecutor’s proffered reason for striking a black panelist applies just as well to an otherwise-similar nonblack who is permitted to serve, that is evidence tending to prove discrimination to be considered at Batson’s third step.” Miller-El v. Dretke, — U.S. -, -, 125 S.Ct. 2317, 2325, 162 L.Ed.2d 196 (2005). In Miller-El, comparative analysis undermined the proffered race-neutral bases for striking two black veniremen because non-blacks who served on the jury should have been excluded for the same reasons. However, here, the prosecutor’s explanation for striking Cerda and Mandujano was consistent with leaving two young whites, Karlberg and Blakely, on the jury. The record is clear that Cerda, unlike Karlberg and Blakely, waffled in response to questions about the imposition of the death penalty.10 Although Mandujano looked *576like a very strong juror, he was younger than Karlberg and Blakely and the only college student, so the prosecutor’s stated nondiscriminatory reasons for striking him are plausible. Therefore, Sims’s comparative argument fails.
IV
Sims claimed in his state habeas petition to the California Supreme Court and in his federal petition that his right to an impartial jury was violated when a member of his jury, Marlene Mauro, met with a friend who had served on Padgett’s jury, agreed to write a book with her, and told this to other jurors.
He submitted the declaration of Sarah Nordell, a Sims juror, in support. Nordell avers that Mauro related to some of the Sims jurors that she learned about her friend’s service on the Padgett jury when they met at a beauty shop and discovered that both occupied the same seat in the jury box, that she and her friend were thinking of writing a book together about the two trials titled something like “Seat Number 3,” and that they were both looking forward to getting together, once the Sims trial was over, to compare their experiences as jurors and to work on their book.11 The supreme court summarily denied relief, and the district court denied Sims’s request for discovery and for an evidentiary hearing on the claim. It held that Nordell’s declaration does not establish any improper communication.
Sims contends that the unauthorized communication between Mauro and her friend is presumptively prejudicial under Mattox v. United States, 146 U.S. 140, 13 S.Ct. 50, 36 L.Ed. 917 (1892), and Remmer v. United States, 347 U.S. 227, 74 S.Ct. 450, 98 L.Ed. 654 (1954). In Mattox, the bailiff told jurors after the jury had retired to deliberate that this was the third fellow the defendant had killed. The Court held that “[pjrivate communications, possibly prejudicial, between jurors and third persons, or witnesses, or the officer in charge, are absolutely forbidden, and invalidate the verdict, at least until their harmlessness is made to appear.” Mattox, 146 U.S. at 150, 13 S.Ct. 50. In Remmer, an unnamed person communicated with a juror and remarked that he could profit by bringing in a verdict favorable to the petitioner. Elaborating upon Mattox, the Court declared that “[i]n a criminal case, any private communication, contact, or tampering directly or indirectly, with a juror during a trial about the matter pending before the jury is, for obvious reasons, deemed presumptively prejudicial!.]” Remmer, 347 U.S. at 229, 74 S.Ct. 450. In Sims’s view, the Mauro contact was especially pernicious as it gave Mauro a real, or perceived, pecuniary interest in the outcome of the case. For this he relies on our statement in Dyer v. Calderon, 151 F.3d 970, 982 (9th Cir.1998) (en banc), that a juror who has “the hope of writing a memoir ... introduces the kind of unpredictable factor into the jury room that the doctrine of implied bias is meant to keep out.”
Dyer involved the situation where a prospective juror perjured herself during voir dire, whereas the alleged impropriety here arose after the juror was empaneled.
*577Whether or not Dyer’s comments about the “hope of writing a memoir” apply in our circumstances is academic, however, because, without condoning the contact— which the state agrees was unfortunate— we see no prejudice resulting from it. “A communication is possibly prejudicial, not de minimis, if it raises a risk of influencing the verdict.” See Caliendo v. Warden, 365 F.3d 691, 697 (9th Cir.2004) (so holding in a case where the case agent talked to several jurors for twenty minutes in the hallway outside the courtroom, and identifying factors that may inform the decision whether the communication raised a risk that the verdict was influenced). Here, taking Nordell’s declaration as true, Mauro’s unauthorized communication did not risk influencing the verdict. The Padgett juror was not involved in any way with the Sims trial; she was not a party, a witness, or a court official. The contact was fortuitous and the communication was of a relatively innocuous nature in that it centered on the serendipity of two friends ending up as jurors in related trials sitting in the same seat. Even if Mauro planned to write a book about “Seat Number 3,” there is no suggestion that she had a financial interest in any particular outcome. This is quite unlike the suggestion by a third-party in Remmer that the juror could make a deal, or the bribery of a juror by a co-defendant in United States v. Dutkel, 192 F.3d 893, 894-95 (9th Cir.1999). As appears from Nordell’s declaration, Mauro intended to wait until after Sims’s trial to discuss her experiences. And there is no indication that Mauro’s communication had any actual impact on her or anyone else. The connection between the allegations contained in the Nordell declaration and any pecuniary interest on Mauro’s part is simply too tenuous to raise a serious concern about undermining impartiality. In these circumstances, the unauthorized communication raised no risk of influencing the' Sims verdict. See United States v. Armstrong, 654 F.2d 1328, 1333 (9th Cir.1981) (finding no prejudice from juror’s receiving obscene phone calls from an unknown person regarding the juror’s treatment of another juror, as the calls did not refer to the merits of the case, were not threatening, and were not identified with either party).
Sims contends that he should at least have been accorded discovery or an evidentiary hearing on the basis of allegations in his petition, but we see no abuse of discretion. See Villafuerte v. Stewart, 111 F.3d 616, 633 (9th Cir.1997) (per curiam) (noting that abuse of discretion is the standard of review). Discovery is indicated where specific allegations give the court reason to believe that a petitioner may be able to demonstrate that he is entitled to relief. Bracy v. Gramley, 520 U.S. 899, 908-09, 117 S.Ct. 1793, 138 L.Ed.2d 97 (1997). An evidentiary hearing is required under pre-AEDPA law if “(1) the petitioner’s allegations would, if proved, entitle him to relief; and (2) the state court trier of fact has not, after a full and fair hearing, reliably found the relevant facts.” Silva v. Woodford, 279 F.3d 825, 853 (9th Cir.2002) (quoting Jones v. Wood, 114 F.3d 1002, 1010 (9th Cir.1997)). Only three things are alleged in Sims’s petition that were not encompassed in the Nordell declaration: that Mauro’s friend told Mauro information from Padgett’s testimony shifting blame to Sims, that Padgett had been convicted and that, in the friend’s opinion, Padgett was a young, beautiful girl who had wasted her life by getting involved with Sims. Assuming the truth of these statements, they could not have had a substantial or injurious effect on the verdict. At trial, Sims did not attempt to exculpate himself by blaming Padgett; indeed, the evidence showed that Sims directed, and committed most of the conduct *578in furtherance of the crimes, himself. The friend’s opinion of Padgett could have had no effect on the verdict at all. And the fact that a number of jurors knew about Padgett’s conviction was aired before the district court, which concluded that any such knowledge was rendered insignificant by the overwhelming evidence of Sims’s guilt. This decision is not pursued on appeal, and we can see no way in light of it that Sims’s allegation that Mauro knew about Padgett’s conviction, if proved, would entitle him to relief.
V
Sims maintains that his rights to due process and a nonarbitrary sentence were violated when the prosecutor told the jury during closing argument in the penalty phase that evidence about Sims’s abusive childhood did not qualify as mitigating evidence and was therefore irrelevant to the jury’s deliberations. The state responds that this is not what happened.
At the penalty phase the jury was instructed in accordance with California Penal Code § 190.3 and 1 California Jury Instructions, Criminal (CALJIC) 8.84.1 (1986 rev.). The instruction identifies eleven factors that a juror must consider in aggravation and mitigation of a capital crime. Factor (k) is the last of these and is a “catch-all” factor that directs the jury to consider “any sympathetic or other aspect of the defendant’s character or record that the defendant offers as a basis for a sentence less than death, whether or not related to the offense for which he is on trial.”12
Sims contends that the prosecutor’s arguments negated this instruction in two respects: first, by telling the jury that the abuse Sims suffered during his childhood, and the depression traceable to it that he suffered as an adult, did not qualify as mitigating evidence in any context when he stated that “if, in fact, it were a mitigating factor that a person had a bad childhood, that would apply to virtually every violent felon currently incarcerated”; and second, by stating that Sims’s background was not a mitigating factor because there was “nothing to bridge the background of what happened in [Sims’s] family to the murders that we have dealt with here.” Sims argued the same points to the California Supreme Court, which concluded that “[t]he prosecutor’s remarks, in general, fall within the bounds of proper argument.” Sims, 5 Cal.4th at 464, 20 Cal.Rptr.2d 537, 853 P.2d 992. It explained that “[f]or the most part, he did not imply that the jury should disregard the evidence of defendant’s background, but rather that, in relation to the nature of the crimes committed, it had no mitigating effect. ‘A prosecutor does not mischaracterize such evidence [offered in mitigation] by arguing it should not carry any extenuating weight when evaluated in a broader factual context.’ ” Id. (internal citations omitted). The supreme court thought that the prosecutor’s comment that the troubled background of a defendant does not constitute mitigating *579evidence might have tended to suggest incorrectly that the jury could not consider such evidence in mitigation, but that any such suggestion was harmless beyond a reasonable doubt given defense counsel’s vigorous argument that Sims’s background had mitigating relevance and instructions that specifically told the jury to consider as mitigating the evidence relating to Sims’s childhood. Id. In these circumstances, the court concluded that there was no reasonable possibility the jury was misled to believe it could not consider Sims’s background in mitigation. The district court agreed. As it read the prosecutor’s summation, he never told the jury to disregard Sims’s history of abuse but instead argued that the evidence lacked mitigating weight because it was unexplained, but that even if it could be viewed as somehow improper, any error was cured by the instructions that admonished the jurors that the prosecutor’s remarks were merely argument and that the court would instruct them on the law. We agree with both courts.
The controlling standard is “whether there is a reasonable likelihood that the jury has applied the challenged instruction in a way that prevents the consideration of constitutionally relevant evidence.” Boyde v. California, 494 U.S. 370, 380, 110 S.Ct. 1190, 108 L.Ed.2d 316 (1990); Brown v. Payton, - U.S. -,-, 125 S.Ct. 1432, 1440-41, 161 L.Ed.2d 334 (2005). The Eighth and Fourteenth Amendments require that the sentencer, “in all but the rarest kind of capital case, not be precluded from considering, as a mitigating factor, any aspect of a defendant’s character or record ... that the defendant proffers as a basis for a sentence less than death.” Lockett v. Ohio, 438 U.S. 586, 604, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978) (plurality opinion) (emphasis in original) (footnotes omitted). If there is constitutional error, that is, if inappropriate comments were made and there is a reasonable likelihood that because of them the jury applied factor (k) in a way that prevented consideration of relevant mitigating evidence, then Brecht harmless error analysis applies. See Calderon v. Coleman, 525 U.S. 141, 146, 119 S.Ct. 500, 142 L.Ed.2d 521 (1998).
In his argument the prosecutor told the jury to be guided by the court’s instructions, which list factors in mitigation, and to make its determinations based upon the instructions. He stated that the various factors in mitigation and aggravation are the law. He explained that mitigating facts would be an aspect of the crime or the individual that make the crime or the individual less vicious, cruel, painful, and deserving of the ultimate punishment. He emphasized that the statute indicates that “you shall consider” the various factors in aggravation and mitigation if applicable. The prosecutor went through each of the aggravating and mitigating factors, arguing which he believed applied. When he got to factor (k), he explained
Now, in this respect, we get into areas of sympathy. Any sympathetic or other aspects of the defendant’s character or background. In this you can consider background, family, anything else ... you can consider whatever you want to find sympathy or pity for the defendant, even though it does not relate to the other factors in mitigation or aggravation.
Discussing Dr. Vicary’s testimony and Sims’s depression, the prosecutor again stated “[i]t is the law you can feel sympathy and pity for a defendant if you deem it appropriate, if you attach a moral or sympathetic value to that.”
The prosecutor described evidence of Sims’s background as “shocking.” He stated that he had no evidence to contra-*580diet it, that it should be taken at face value, and that it paints a very ugly picture. He then posed the rhetorical question: What does it mean? The prosecutor’s answer was: “There is nothing to bridge the background of what happened in that family to the murders that we have dealt with here, nothing to connect it.” Relying on Vicary’s testimony that most people in prison for violent offenses were themselves the victims of abuse when they were younger, the prosecutor stated that “if, in fact, it were a mitigating factor that a person had a bad childhood, that would apply to virtually every violent felon currently incarcerated. If that were, therefore, a mitigating factor, then you would be emptying prisons because it would apply to virtually everybody.”13 The prosecutor pointed out that Vicary never said that mental disease or defect or emotional disturbance were produced by the acts perpetrated on Sims’s family. The prosecutor contrasted the absence of a bridge for these murders with the bridge that might exist, for example, in an offense against Sims’s stepfather, or an offense involving rape or child abuse. He noted that Vicary did testify that Sims suffered depression, child abuse, and low self-esteem, but argued that it did not result in a mitigating factor because, as Vicary also testified, Sims’s depression was somewhere between the mental illness suffered by 20 million people and that suffered by people in Boston when the Celtics lost the playoffs — which, the prosecutor submitted, does not mitigate three murders and two attempted murders.
Overall, the prosecutor’s statements do not suggest that the jury cannot consider Sims’s background as a mitigating factor but rather that it should not find that his background, shocking though it was, mitigated the vicious murders he committed and attempted. Cf. Payton, 125 S.Ct. at 1436-37 (describing the prosecutor’s argument there as erroneously telling the jury that it could not consider post-crime reform and religious conversion as mitigating under factor (k)). He emphasized that the jurors must follow the instructions, must consider mitigating evidence, must take Sims’s background and anything else into account, must take Sims’s evidence of abuse at face value, and must feel sympathy and pity if the jury deems it appropriate. Given these entirely correct statements, we cannot conclude that the prosecutor’s remarks about a missing bridge or emptying prisons created a reasonable likelihood that the jury misapplied the factor (k) instruction so as to preclude consideration of Sims’s background. See Boyde, 494 U.S. at 384-86, 110 S.Ct. 1190 (rejecting contention that prosecutor’s arguing that the mitigating evidence did not “suggest that [petitioner’s] crime is less serious or that the gravity of the crime is any less,” and that “[n]othing I have heard lessens the seriousness of this crime” undermined the factor (k) instruction).
Even if the jurors heard the prosecutor’s closing differently from the way we have read it, and even if the jurors inferred from any of his remarks that he believed Sims’s background should be ignored as the California Supreme Court concluded, it is evident that in the whole context of the case, the prosecutor’s remarks could not have substantially influenced the verdict. The court admonished *581the jury that statements of the attorneys were simply argument, and that the jury would determine what the evidence was and the court would instruct on the law. The prosecutor reminded the jury that the court’s instructions would define the law and that the instructions must be followed. The instructions clearly stated that the jury “shall” consider “any sympathetic or other aspect of the defendant’s character or record that the defendant offers as a basis for a sentence less than death, whether or not related to the offense for which he is on trial.” Sims presented significant evidence of horrific abuse and what impact that abuse had on'him. The prosecutor accepted the evidence as true and acknowledged it was “shocking.” Defense counsel told the jury that “what [he and the prosecutor] disagree on, however, is the significance of the mitigating factor or factors and what weight should be accorded them.” He emphasized that factor (k) is the “sum and substance of Mitchell’s life before December 2, 1985.” Sims’s .attorney countered the prosecutor’s “bridge” argument by explaining that it was wrong, and that while Sims had choices as the prosecutor argued, the “scar tissue builds up and you keep it inside and then it comes out and it explodes in some people.” He explained why the jury should weigh the evidence of Sims’s childhood background and adult depression heavily as factors in mitigation. Finally and most importantly, for the jury to have believed it could not consider Sims’s mitigating evidence, it would have had to believe that Dr. Vicary conducted an extensive examination of Sims, and that Sims’s mother, his sister, his stepbrother, and his wife came out to California to testify, for naught. We think this is unlikely, as the Court thought of the similar situation in Boyde. See Boyde, 494 U.S. at 383-84, 110 S.Ct. 1190 (observing that it is unlikely that reasonable jurors would believe that the court’s instructions on factor (k), even if ambiguous, transformed all of the defendant’s favorable testimony into a “virtual charade”). We thus conclude that any Boyde error was harmless.
VI
Although trial counsel, Morton Borenstein, presented evidence at the penalty phase about Sims’s abusive childhood, Sims contends that he failed to present expert testimony establishing: (1) that Sims suffers from Post-Traumatic Stress Disorder (PTSD) as a result of the abuse he suffered as a child; (2) that- the abuse Sims suffered played a direct role in his involvement with Padgett and in the crimes at issue; (3) that Sims has organic brain damage; and (4) that Sims demonstrated good adaptability to confinement. Sims argues that expert testimony establishing all of these points was readily available and if the jury had known about the full range of mitigating evidence, it is highly likely that Sims would not have been sentenced to death. The district court conducted an evidentiary hearing on this issue and found that Borenstein’s performance was neither deficient nor prejudicial. In a federal habeas action factual findings by the district court are accepted unless they are clearly erroneous. Hendricks v. Calderon, 70 F.3d 1032, 1036 (9th Cir.1995) (as amended).
Borenstein had been a deputy public defender for sixteen years and was a Grade IV (the highest grade) defender at the time he was assigned to Sims’s case. He had tried a number, of special circumstances cases. Although the Sims case was the first he had tried through the penalty phase, Borenstein had been preparing to do capital cases for a long time. He attended seminars and meetings about the death penalty; watched death penalty trials, and spoke with other attorneys *582about issues attendant to capital cases. Borenstein worked long hours consistently on Sims’s case for eleven months; he was assisted by a paralegal and two investigators as well as by an experienced South Carolina attorney familiar with death penalty issues, Jack Swerling.14 Borenstein’s other cases were reassigned before Sims’s trial began and he then worked exclusively on it.
The district court found that Borenstein sent Swerling extensive materials and was in regular communication with him while he prepared Sims’s defense. Swerling and his law clerk interviewed witnesses and obtained Sims’s school and work records. Borenstein traveled to South Carolina personally to speak with family members and witnesses and to view the crime scene.
Borenstein spoke with Sims “a lot” and he or his paralegal visited Sims in jail at least 24 times between March 6, 1986, when Borenstein was assigned to the case, and March 10, 1987, when the trial began.
Borenstein retained the services of two experts: Dr. William Vicary, a forensic psychiatrist, and Dr. Michael Maloney, a forensic psychologist, so that he could have the benefit of opinions from experts in both disciplines. Vicary was a board-certified forensic psychiatrist who received his medical degree from the University of Southern California in 1973 and a law degree from Harvard in 1969. Most of his practice was devoted to conducting evaluations of individuals charged with felonies in the Los Angeles Superior Court. Boren-stein gave Vicary a nine-page single-spaced letter outlining the crimes and Sims’s background, and Vicary also had extensive conversations with Borenstein, who gave him significant details about Sims’s background. Vicary interviewed Sims six times, and interviewed Sims’s mother, wife, siblings, and jail deputies. He reviewed police reports, Sims’s school, army, and work records, his South Carolina therapy records, psychiatric records, and court records regarding Cranford’s prosecution for sexually abusing Margaret. Vicary also conferred with Maloney on the results of Sims’s psychological testing. Vi-cary never told Borenstein that he needed any additional material to evaluate Sims’s case, or that additional testing or experts were needed.
Maloney had a Ph.D. in Psychology from the University of Colorado and completed his post-doctoral fellowship at the University of Southern California Medical Center. He was a Diplómate in Forensic Psychology licensed to practice in California since 1970. Maloney was retained to “conduct a psychological evaluation of Sims to determine the existence of any possible mental defenses for the guilt phase, and to identify any factors that could be considered as mitigating evidence in the event the case proceeded to a penalty phase.” Boren-stein selected Maloney because he had extensive experience in capital cases as well as issues involving allegations of physical, emotional and sexual abuse. Maloney was familiar with the potential impact of physical and sexual abuse on an individual’s development. Borenstein also chose Malo-ney because he would give him an honest opinion and would point him in the right direction if other things were needed. Borenstein sent Maloney the same nine-page letter he sent Vicary, as well as re*583ports of interviews conducted with Sims’s family, friends, and high school principal, and Sims’s military records. He and Ma-loney also met several times and discussed the case at length. Maloney interviewed Sims several times and administered several tests, including: the Wechsler Adult Intelligence Scale Revised, the Minnesota Multiphasic Personality Inventory, and the Rorschach inkblot test. Maloney concluded that Sims was of “clearly above average intelligence” and that there were no mental defenses to the crimes. Sims showed a disparity between his Verbal and Performance IQ scores, but Maloney believed that the disparity could be attributed to factors other than neuropsychological deficits. In his opinion, Sims also showed signs of antisocial personality disorder. Maloney never told Borenstein that he lacked any background materials to conduct the evaluation, nor did he suggest that additional testing was needed or that additional experts should be retained. Maloney indicated to Borenstein that he did not believe he would be a good witness for Sims because of what he had discovered in his testing, and Borenstein decided not to have Maloney testify because of this.
Vicary did testify, relating in light of his interviews and investigation that Sims had suffered'a lengthy pattern of abuse (along with other members of his family), had been suicidal since the age of fifteen, and had a history of drug and alcohol abuse as well as long-standing feelings of inadequacy, low self-esteem, despair, shame, and humiliation. He explained that these feelings cause the victims to become more and more frightened that, as they succeed, people will find out who they really are and that they can not actually handle responsibilities. This in turn can result in their intentionally or unintentionally creating a situation so that the anticipated negative feedback occurs. Vicary also opined that Sims suffered chronic depression.
The district court held an evidentiary hearing at which testimony was received from Borenstein and eight experts.15 The district court found that Borenstein conducted an extensive investigation regarding Sims’s background and the crimes, retained well-qualified experts experienced *584in capital cases to whom he reported the results of his investigation, and was not told by either expert that additional information or expertise was needed. With respect to the claims that Sims now makes, the court found that Borenstein identified that brain damage was a possibility, conducted a thorough investigation, and provided the results of his investigation to the experts. Experts testified convincingly at the hearing that the disparity in Sims’s verbal and performance IQ was not indicative of brain damage, and that Sims’s own calculated actions during the crimes belie any claim that he suffered an impairment in frontal lobe functioning. With respect to PTSD, the court determined that in Vicary, Borenstein hired an expert who was exceptionally qualified to render a diagnosis based on Sims’s history of childhood sexual abuse, and Vicary admitted that he had knowledge of PTSD. Finally, the court found that Sims minimized Pad-gett’s involvement in the crimes during conversations with Borenstein and that Borenstein saw signs that Sims was the domineering partner even though he was a “fool” for Padgett. Borenstein discussed Padgett’s influence on Sims with Maloney, watched Padgett testify at her trial, and based on all these things, concluded that there was nothing about the relationship that he could effectively use to mitigate the heinous nature of the crimes. Boren-stein was also concerned that if he exploited Sims’s relationship with Padgett, the prosecution would call her as a witness and if so, that she would testify as she did at her trial that Sims forced her to go to California and how Sims cut rope and laid out which portions he would use to tie up Harrigan’s hands and feet, laid out a washcloth and socks that he planned to use to gag the victim, and considered drowning the victim or cutting his throat. Thus, the court found that Borenstein’s decision not to present evidence regarding Padgett’s effect on Sims was a reasonable strategic decision. Finally, the court found that Borenstein also made a reasonable tactical decision not to pursue future dangerousness because it would open the door for the prosecution to present evidence of a crime that Sims committed in the Army, another structured setting.
Suffice it to say, the district court’s findings are fully supported. At the end of the day, Sims’s argument turns on a latter-day battle of experts; however, the question is whether counsel did all that he was constitutionally required to do at the time. As carefully explained by the district court, it is clear that Borenstein did. Indeed, Sims submitted no evidence during the evidentiary hearing from experts in the legal community that Borenstein’s performance fell short of prevailing legal norms.
The legal framework is well-settled. In order to prevail on a claim for ineffective assistance of counsel a defendant must show (1) that his counsel’s representation “fell below an objective standard of reasonableness”; and (2) that counsel’s deficient performance “prejudiced” the defense. Strickland v. Washington, 466 U.S. 668, 688, 692, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984). Defense counsel “must conduct sufficient investigation and engage in sufficient preparation to be able to ‘present[ ] and explain! ] the significance of all the available [mitigating] evidence.’ ” Mayfield v. Woodford, 270 F.3d 915, 927 (9th Cir.2001) (en banc) (quoting Williams v. Taylor, 529 U.S. 362, 120 S.Ct. 1495, 146 L.Ed.2d 389 (2000)). “[Strategic choices made after thorough investigation of law and facts relevant to plausible options are virtually unchallengeable; and strategic choices made after less than complete investigation are reasonable precisely to the extent that reasonable professional judgments support the limitations on investiga*585tion.” Strickland, 466 U.S. at 690-91, 104 S.Ct. 2052. In determining whether counsel’s conduct falls within the broad range of professionally acceptable conduct, this court “will not view counsel’s actions through the distorting lens of hindsight. Rather, under the rule of contemporary assessment, an attorney’s actions must be examined according to what was known and reasonable at the time the attorney made his choices.” Hendricks, 70 F.3d at 1036 (internal quotations and citations omitted). Counsel has “an obligation to conduct an investigation which will allow a determination of what sort of experts to consult. Once that determination has been made, counsel must present those experts with information relevant to the conclusion of the expert.” Caro v. Calderon, 165 F.3d 1223, 1226 (9th Cir.1999). Finally, a court must indulge a strong presumption that counsel’s conduct falls within the wide range of reasonable professional assistance. Bell v. Cone, 535 U.S. 685, 702, 122 S.Ct. 1843, 152 L.Ed.2d 914 (2002).
Borenstein did not fall short of the mark in any of the respects claimed by Sims. First, he did not unreasonably fail to retain an expert who could properly analyze the impact of childhood abuse, in particular, PTSD. Vieary was qualified to do so, as he admitted.
Second, Borenstein did not unreasonably fail to elicit expert testimony explaining the dynamics of Sims’s relationship with Padgett; he informed Vieary about Pad-gett, and Vieary interviewed Sims a number of times knowing that Padgett was his girlfriend and accomplice. Vieary had nothing positive to say about the dynamics, perhaps because Sims had said that he told Padgett what his plans were and she protested but was scared of him and he wouldn’t let her leave. Sims submits that Borenstein could not make a reasonable strategic decision to forego assessing Pad-gett’s impact on Sims because he could only make this call if it were informed by an investigation into Padgett’s background. While the investigation supporting counsel’s decision not to introduce mitigating evidence must itself be reasonable, see, e.g., Wiggins v. Smith, 539 U.S. 510, 522-23, 526, 123 S.Ct. 2527, 156 L.Ed.2d 471 (2003); Williams v. Taylor, 529 U.S. 362, 120 S.Ct 1495, 146 L.Ed.2d 389 (2000); Jennings v. Woodford, 290 F.3d 1006, 1014 (9th Cir.2002), it is immaterial that Borenstein did not investigate Pad-gett’s background because it was Sims’s perspective on the relationship that mattered. Sims’s experts evidently thought so as well, as their testimony at the evidentia-ry hearing focused on the relationship from Sims’s point of view.
Third, Borenstein did not unreasonably fail to pursue the possibility that Sims had organic brain damage. Maloney alerted Borenstein to the possibility, but found none. He did not advise Borenstein to retain a specialist in neurological impairment to pursue the possibility. Some experts who testified at the evidentiary hearing agreed with Maloney’s diagnosis, others didn’t.16 But there is no evidence that Maloney was not qualified; the district court- found that he was well-regarded by the defense bar, prosecutors and judges alike. In these circumstances, as we explained in Hendricks, attorneys are entitled to rely on the opinions of mental health experts, and to impose a duty on them to investigate independently of a request for information from an .expert *586would “defeat the whole aim of having experts participate in the investigation.” 70 F.3d at 1038, 1039.
Fourth, Borenstein did not unreasonably fail to elicit testimony from Vieary about Sims’s adaptability to confinement. Vi-cary’s optimistic assessment would have been severely undercut by Sims’s bad conduct discharge from the Army for a crime that involved the use of force or violence and which would have been admissible as aggravating evidence during the penalty phase. Cal.Penal Code § 190.3(b). Without doubt Borenstein’s decision to keep this door closed was reasonable.
In sum, by contrast with other cases in which the Supreme Court or we have found deficient performance,17 Sims’s counsel thoroughly prepared for the penalty phase, retained and informed well-qualified experts upon whom he could reasonably rely, and presented heart-wrenching evidence in mitigation. His performance passes constitutional muster.
VII
Sims argues that during the prosecutor’s summation at the penalty phase, he made numerous impermissible comments about Sims’s silence regarding *587whether Sims was sorry for the crimes he committed, which invited the jury to penalize him for exercising his Fifth Amendment right not to testify.18 Borenstein did not make a Griffin19 objection, and Sims claims that this amounted to ineffective assistance of counsel with respect to these statements:
I was waiting for Mitchell Sims to express remorse, to apologize to somebody for what he had.done and what he had taken. What I he^rd was a preoccupation with getting cigarettes, seeing his girlfriend Ruby Padgett. I did not hear any of that remorse. Anything that would tell me that Mitchell Sims will be living the rest of his life with his stomach in a knot. That he will be preoccupied with the evil he has done. There is nothing like that.
Now, at no time did I hear any remorse. Hear a tear. I mean, we have all felt guilty about things in life. It’s a human reaction, but granted, we haven’t killed people. We are not mass murderers. But there was no feeling of guilt. There is absolutely no feeling of guilt.
The life in prison, is he going to spend it brooding and contemplating about the evil he has done? You really think he will? You think he is going to have that knot in his stomach? You think he will think about the Uves he has taken? The years he has stolen? Has he yet? Has he yet come out and said to anyone that tearfully he is sorry for what happened, that he thinks about it every day, that he can’t sleep at night?
However, the statements must be considered in context. In context, the first statement -to which Sims says counsel should have objected is as follows:
Now, many things go into a case in judging what the appropriate punishment should be and we have a statement to Mr. Perkins on the 25th, the taped conversation that I would like you — respectfully ask you to listen to for several reasons — on the 26th, and we have Dr. Vicary who said he interviewed the defendant 6 times’ for a total of 6 hours.
And I was waiting for those pieces of evidence to hear that Mitchell Sims was sorry. I was waiting to hear that Mitchell Sims felt bad about the years he had stolen.' I was waiting for Mitchell Sims to express remorse, to apologize to somebody for what he had done and what he had taken.
What I heard was a preoccupation with getting cigarettes, seeing his girlfriend *588Ruby Padgett. I did not hear any of that remorse. Anything that would tell me that Mitchell Sims will be living the rest of his life with his stomach in a knot. That he will be preoccupied with the evil he has done. There is nothing like that.
The second is:
Next day Mitchell Sims calls back Jon Perkins and conversation picks up again about cigarettes. First thing on Mitchell Sims’ mind is cigarettes. He has killed 3 people, tried to kill 2 more, and the first thing on his mind is cigarettes; the second one is Ruby.
And he says, “Well, I knew I was doing it,” and then kicks in as an afterthought, “Maybe I shouldn’t have done it.” That’s the only thing, the closest thing we have to even remotely showing any remorse for what he did. And that was dropped immediately because he said, “Oh, well, I was drunk.”
[colloquy]
Now, at no time did I hear any remorse. Hear a tear. I mean, we have all felt guilty about things in life. It’s a human reaction, but granted, we haven’t killed people. We are not mass murderers. But there was no feeling of guilt. There is absolutely no feeling of guilt.
Listen to this tape. Listen to the tone of his voice on [that] tape, and ask yourself where is the guilt? Where is the remorse? Where is the repentance? Where is asking for forgiveness there? You won’t find it.
And the third is:
His world, we learned a little bit about when we heard first from Mrs. Sims and then from Detective Yarborough about his fascination with the movie “The Executioner’s Song.” About Gary Gilmore who was himself a multi-murderer, about how Sims wanted to go out in a blaze of glory. That is his world. Fascination with multiple murderers. That’s his world. A life in prison, that’s what his world will be like. That’s what he will be like. The life in prison, is he going to spend it brooding and contemplating about the evil he has done? You really think he will? You think he is going to have that knot in his stomach? You think he will think about the lives he has taken? The years he has stolen? Has he yet? Has he yet come out and said to anyone that tearfully that he is sorry for what happened, that he thinks about it every day, that he can’t sleep at night? That he can’t eat? That he feels guilty and he can’t take it any longer? Will he spend the rest of his life in remorse or will it be like you hear on the tape: cigarettes, Ruby, me first, satisfy my needs today.
Each of these comments is tethered to evidence that was part of the record in the penalty phase, as the district court found. For this reason, Sims’s contention — that the prosecution may not argue that the defendant has failed to show remorse by using his silence at trial as the evidence of remorselessness — while true in the abstract, is misplaced. We held in Beardslee v. Woodford that “[a] prosecutor’s comment is impermissible if it is ‘manifestly intended to call attention to the defendant’s failure to testify or is of such a character that the jury would naturally and necessarily take it to be a comment on the failure to testify.’ ” 358 F.3d 560, 586 (9th Cir.2004) (quoting United States v. Tarazon, 989 F.2d 1045, 1052 (9th Cir.1993)). However, the situation and the prosecutor’s statements in Beardslee were both quite different from the situation and the prosecutor’s statements here. Beard-slee had testified at a preliminary hearing and at the guilt phase. In that light, the prosecutor’s comments implied that the defendant’s failure to testify at the penalty *589phase had significance when he stated: “Since you only heard the defendant through the tape recorder and his previous testimony, you were not able to observe his demeanor and sincerity at the time he testified so you, too, could judge if there was any feeling in the man.... Wouldn’t you expect a man on trial for his life would, through his statements, cry out for forgiveness, cry out for pity? He did not. Never heard any in the statements.” Id. Nothing similar occurred at the Sims trial or could have been inferred from the prosecutor’s remarks, which .rested entirely upon statements that Sims himself had made. The prosecutor made no allusion to the difficulty of gauging an absent defendant’s credibility. This being so, counsel’s failure to object to the prosecutor’s statements did not fall below an. objective standard of reasonableness.
VIII
As with the individual claims, we conclude that the cumulative effect of any constitutional errors did not prejudice Sims.
AFFIRMED.
. Our recitation of the facts is primarily based on the California Supreme Court’s summary, Sims, 5 Cal.4th at 418-27, 20 Cal.Rptr.2d 537, 853 P.2d 992, which is presumed to be correct. Bragg v. Galaza, 242 F.3d 1082, 1087 (9th Cir.2001).
. Following the trial in this case, Sims was tried and convicted in South Carolina of the murders of Melkie and Zerr during the commission of a robbery, and the death penalty was imposed. The convictions and sentence of death were affirmed by the Supreme Court of South Carolina. State v. Sims, 304 S.C. 409, 405 S.E.2d 377 (1991), cert. denied, 502 U.S. 1103, 112 S.Ct. 1193, 117 L.Ed.2d 434 (1992).
. Justice Mosk dissented from the Chapman analysis; Justice Kennard wrote in her concurring and dissenting opinion that she would have held that Sims initiated conversation on both days and waived his right to counsel.
. Brecht v. Abrahamson, 507 U.S. 619, 637, 113 S.Ct. 1710, 123 L.Ed.2d 353 (1993) (holding that a federal court may only grant habeas relief from a state court judgment if constitutional error "had substantial and injurious effect or influence in determining the jury's verdict" (quoting Kotteakos v. United States, 328 U.S. 750, 776, 66 S.Ct. 1239, 90 L.Ed. 1557 (1946))).
. We review de novo a district court’s denial of a habeas petition filed under 28 U.S.C. § 2254. Clark v. Murphy, 331 F.3d 1062, 1067 (9th Cir.2003). A district court’s factual findings are reviewed for clear error. Alcala *569v. Woodford, 334 F.3d 862, 868 (9th Cir.2003). In pre-AEDPA cases such as this, we review legal questions and mixed questions of law and fact de novo. Mayfield v. Woodford, 270 F.3d 915, 922 (9th Cir.2001) (en banc). State court findings of fact are presumed correct to the extent they are "fairly supported by the record.” 28 U.S.C. § 2254(d) (1994); Mayfield, 270 F.3d at 922.
. See, e.g., Rhode Island v. Innis, 446 U.S. 291, 301, 100 S.Ct. 1682, 64 L.Ed.2d 297 (1980) (holding that interrogation under Miranda refers to words or actions by the police that they "should know are reasonably likely to elicit an incriminating response”); Edwards v. Arizona, 451 U.S. 477, 485, 101 S.Ct. 1880, 68 L.Ed.2d 378 (1981) (holding that once an accused asserts his right to the presence of counsel he must himself "initiate[] further communication, exchanges, or conversations with the police” before further interrogation may take place); Oregon v. Bradshaw, 462 U.S. 1039, 1045-46, 103 S.Ct. 2830, 77 L.Ed.2d 405 (1983) (plurality opinion) (holding that once an accused asserts the fight to counsel, re-initiation occurs when he "evince[s] a willingness and a desire for a generalized discussion about the investigation”); see also Shedelbower v. Estelle, 885 F.2d 570, 573 (9th Cir.1989) (holding that an officer’s false statement that the suspect had been identified by a rape victim was not the type of comment that would encourage the accused to make some incriminating spontaneous remark); United States v. Moreno-Flores, 33 F.3d 1164, 1169 (9th Cir.1994) (holding that agent's statements that the government had seized cocaine, the accused was in serious trouble, and he faced a lengthy prison sentence were not the functional equivalent of interrogation because they did not invite a response); United States v. Orso, 266 F.3d 1030, 1033-34 (9th Cir.2001) (en banc) (holding that officer should have known it was reasonably likely that engaging in discussion about evidence and witnesses against the accused as well as the penalties for the crime would cause the suspect to respond).
. See, e.g., Spicer v. Gregoire, 194 F.3d 1006, 1008 (9th Cir.1999) (assuming constitutional error and finding it harmless).
. Whether the verdict was "surely affected" is not the standard by which we measure harmless error. Sims apparently drew the concept from Sullivan v. Louisiana, 508 U.S. 275, 279, 113 S.Ct. 2078, 124 L.Ed.2d 182 (1993), which discussed the distinction between structural error and Chapman harmless error review of trial errors — noting in that connection that the verdict must be "surely unattributable" to error. However, Chapman does not apply to federal habeas review.
. People v. Wheeler, 22 Cal.3d 258, 148 Cal.Rptr. 890, 583 P.2d 748 (1978), is the California analogue of Batson, although it has somewhat different standards. Our review, of course, is for federal constitutional error under Batson. The United States Supreme Court recently rejected the standard that California required under Wheeler for a prima facie showing. Johnson v. California, — U.S. -, 125 S.Ct. 2410, 162 L.Ed.2d 129 (2005). However, Johnson does not affect our analysis because Sims's appeal does not turn on the prima facie case.
. Sims's suggestion that the California Supreme Court and the district court crafted an additional ground that Cerda had equivocal feelings about the death penalty is misplaced, as Cerda's equivocal responses to questions about the death penalty showed lack of maturity that reasonably led the prosecutor to doubt her ability to "take on” a death case. Cf. Miller-El, 125 S.Ct. at 2332 (explaining that a court’s "substitution of a reason for eliminating [a prospective juror] does nothing to satisfy the prosecutors’ burden of stating a racially neutral explanation for their own actions”).
. The state suggests that the Nordell declaration has multiple layers of hearsay and so Sims did not present the California Supreme Court with competent evidence of this allegation, thus making it noncognizable on federal habeas review. It is unclear to us that this point was raised in district court, but in any event, we decline to avoid the issue on this basis. See Jeffries v. Blodgett, 5 F.3d 1180, 1189-91 (9th Cir.1993) (considering two juror affidavits filed two years after petitioner was sentenced that recounted the remarks of a third juror).
. With respect to factor (k), the jury was instructed:
In determining which penalty is to be imposed on the defendant, you shall consider all of the evidence which has been received during any part of the trial of this case. You shall consider, take into account, and be guided by the following factors if applicable ... K, any other circumstance which extenuates the gravity of the crime, even though it is not a legal excuse for the crime, and any sympathetic or other aspect of the defendant’s character or record that the defendant offers as a basis for a sentence less than death, whether or not related to the offense for which he is on trial.... You, and each of you, are the sole judges of whether a factor is an aggravating or a mitigating factor.
. Vicary testified during the sentencing phase that "the vast majority” of people who are in prison for violent sexual offenses, rape, and child molesting, were, themselves, the victims of some sort of abuse when they were younger. He also testified that "in the vast majority of cases” that people who commit acts of premeditated murder, were themselves abused as children.
. Borenstein arranged for Swerling's appointment so that Swerling could investigate Sims's background and the South Carolina crimes. Swerling had defended some 100 homicides, four of which involved the death penalty. He was an adjunct professor of criminal trial advocacy at the University of South Carolina Law School, and had served as chair of the criminal law sections of the South Carolina Bar Association and the South Carolina Trial Lawyers Association.
. Dr. Whyte, a psychiatrist, testified that he believed Sims suffered from PTSD, alcohol dependence, and a personality change due to organic brain damage; he disagreed with Ma-loney and Dr. Ornish who determined that Sims suffered from antisocial personality disorder. Dr. Lebowitz, a psychologist licensed as a healthcare provider in Massachusetts, assessed Sims as tormented, impaired and desperate so far as Padgett was concerned. Dr. Venn, a psychologist, diagnosed Sims with PTSD and explained that Sims's history of severe sexual abuse affected him profoundly; that Sims suffers anxiety, depression, and low self-esteem; and that Sims meets the DSM-IV criteria for alcohol dependence, although when he originally interviewed Sims in 1992 and 1993, he diagnosed him with anti-social disorder. Vicary stated that he did not realize that Maloney had administered a shortened version of some tests to Sims; that he did not consider a diagnosis of PTSD; that details of Padgett’s life would have helped him explain why the offenses occurred; and that he was prepared to offer testimony that Sims would adapt well to confinement. Dr. Halleck reviewed the expert reports, and Dr. Hamrick, who testified in Sims's South Carolina trial, opined that the difference in Sims’s IQ scores would generally indicate at least some mild brain dysfunction. Dr. Delis was a neuropsychologist who found no evidence of brain damage that affected Sims's cognitive ability, or of frontal lobe cognitive dysfunction. Dr. Ornish is a forensic psychiatrist who determined that Vicary’s trial assessment of Sims was competent; that Sims had antisocial personality disorder, alcohol dependence and a history of substance abuse; that it was inappropriate to diagnose brain damage solely based on differences between verbal and performance IQ, and that there was no other evidence of brain damage; and that Sims was a textbook sociopath and substance abuser.
. Sims is extremely intelligent, and scored in the 99th percentile on the most sensitive test of frontal-lobe dysfunction, in the top two percent of people in the country on a comprehension test, and average to above average in higher level cognitive functioning but in many ranges is in the top ten percent of the population.
. See, e.g., Wiggins, 539 U.S. at 510, 123 S.Ct. 2527 (counsel performed deficiently where they failed to put on any evidence of petitioner's life history; failed to follow up on preliminary information suggesting that petitioner had a horrific and traumatic childhood; and failed to comply with the standards of performance established in their state and by the ABA at the time of trial); Williams, 529 U.S. at 362, 120 S.Ct. 1495 (counsel performed deficiently where he did not begin to prepare for sentencing until one week before trial; did not obtain records on petitioner’s background; did not obtain petitioner’s prison records which revealed adaptability to confinement; and failed to return call of witness who offered favorable testimony regarding petitioner); Allen v. Woodford, 395 F.3d 979 (9th Cir.2005) (counsel failed to prepare for the sentencing phase of capital case until a week before that phase began and failed to present available mitigation and the failure was deemed harmless); Mayfield v. Woodford, 270 F.3d 915, 927 (9th Cir.2001) (en banc) (counsel billed only 40 hours in preparation for guilt and penalty phases, only substantively met with the client once, and bn the day trial commenced, failed to obtain relevant material records, spent less than half the allowed budget and failed to consult relevant experts despite being alerted to “evidence of diabetes and substance abuse ... ”); Lambright v. Stewart, 241 F.3d 1201 (9th Cir.2001) (counsel failed to obtain psychiatric evaluation despite knowing of petitioner’s traumatic wartime experience and extensive drug abuse); Bean v. Calderon, 163 F.3d 1073, 1078 (9th Cir.1998) (completely unprepared attorney presented only “disorganized and cursory” penalty phase); Turner v. Duncan, 158 F.3d 449, 456 (9th Cir.1998) (counsel’s failure "to arrange a psychiatric examination or utilize available psychiatric information also falls below acceptable performance standards”); Seidel v. Merkle, 146 F.3d 750 (9th Cir.1998) (counsel was ineffective for failing to conduct any investigation into defendant's psychiatric history despite evidence that defendant had been treated for mental illness); Caro, 165 F.3d at 1228 (counsel’s performance was deficient because, although aware of his acute and chronic exposure to toxic chemicals, counsel did not acquire any experts on the effects of chemical poisoning, did not provide the experts who did examine Caro with the information that he had, and failed to properly consult experts); Wallace v. Stewart, 184 F.3d 1112, 1118 (9th Cir.1999) (petitioner stated prima facie case for ineffective assistance during penalty phase where there was complete failure to investigate family or background despite evidence suggesting petitioner had mental problems); Jennings, 290 F.3d 1006 (counsel was ineffective where he failed to inquire into possible child abuse in the family, failed to appoint additional experts to evaluate Jennings’s mental state or the possible effects of methamphetamine on a heavy, long-time user, despite the fact that he knew that Jennings had been "strung out” for over a year, did not discuss the effects of Jennings's drug use with Jennings himself, nor did he follow up on a report that Jennings had attempted suicide, that Jennings was schizophrenic, and that his ex-wife believed that he was crazy).
. Sims's argument has shifted from his position before the California Supreme Court, where his argument appeared to be that the prosecutor improperly urged the jury to consider his lack of remorse'. The supreme court found this argument was procedurally defaulted because Sims failed to object, and that in any event the prosecutor properly suggested that lack of remorse should weigh against the jurors’ assigning significance to the mitigating evidence. Sims, 5 Cal.4th at 465, 20 Cal.Rptr.2d 537, 853 P.2d 992. The district court noted that in addition to this point, Sims further contended in his federal habeas proceeding that by referring to his lack of remorse, the prosecutor impermissibly commented on his failure to testify. It concluded that the claim was procedurally barred because the California Supreme Court invoked the contemporaneous objection rule. The district court also found the claim lacked merit, because the prosecutor did not refer to Sims's failure to testify in describing Sims’s lack of remorse.
. Griffin v. California, 380 U.S. 609, 615, 85 S.Ct. 1229, 14 L.Ed.2d 106 (1965) (forbidding comment by the prosecution on the accused’s silence). Counsel did object on Griffin grounds to the prosecutor's reference to Sims's statement to Perkins on December 26 that he preferred not to discuss what happened inside the store in Hanahan.