The opinion of the Court was delivered by
CLIFFORD, J.Defendant, Nathaniel Harvey, appeals from a capital-murder conviction and death sentence. Because the trial court’s jury instructions at the guilt phase did not comply with our later holding in State v. Gerald, 113 N.J. 40, 549 A.2d 792 (1988), we reverse the conviction and remand for a new trial.
I
—A—
After Irene Schnaps failed to appear for work on June 17, 1985, a colleague went to her apartment at the Hunter’s Glen complex in Plainsboro. When no one answered, he entered through the unlocked door and found Schnaps dead on the bedroom floor. She had suffered severe head and facial wounds.
The police found an empty box for a Seiko LaSalle watch on the dressing table in the bedroom. An empty camera box was in the closet, and an open purse sat atop the vanity in the bathroom. A pillowcase had a bloody sneaker print bearing a chevron design and the letters “PON.” There were no signs of forced entry; the sliding glass door was closed but unlocked.
Dr. Martin Shuster performed an autopsy. He concluded that Schnaps had suffered numerous skull fractures, a fractured jaw, and a deep laceration on her skull. Dr. Shuster believed that she had been struck at least fifteen times with a blunt object. Pressure applied to her neck for an hour had caused contusions. In Dr. Shuster’s opinion, a brief interval separated the first blow and death. He could not determine *412which blows had been fatal and which had been inflicted after the victim’s death.
—B—
On October 28, 1985, the police arrested defendant on suspicion of kidnapping and burglary. Following several interrogations over the next three days, defendant admitted that he had killed Irene Schnaps. He said that on June 16 he had gone to the Hunter’s Glen apartment complex. Entering Schnaps’ apartment through an unlocked patio door, he went into the bedroom, where he took a watch and some jewelry from the dresser. Schnaps, who had been sleeping, woke up and punched him in the nose, causing it to bleed. Defendant then struck her in the head with a “hammer-like” object, knocking her to the ground. Afraid that the blood from his nose had stained the sheets, he replaced them with clean ones from the closet. He then retrieved a towel from the bathroom and wiped the blood off of Schnaps’ body. After collecting the bed sheets, the towel, the watch, a camera, and other pieces of jewelry, he left the apartment.
A jury convicted defendant of the knowing and purposeful murder of Irene Schnaps, felony murder, first-degree robbery, and second-degree burglary. Following a penalty-phase proceeding on the capital-murder conviction, the trial court sentenced defendant to death.
II
We first consider defendant’s contention that the trial court’s failure to instruct the jury separately for the crimes of knowingly or purposely causing death (intentional murder) and of knowingly or purposely causing serious bodily injury resulting in death (serious-bodily-injury murder) requires reversal of his conviction. In State v. Gerald, supra, 113 N.J. at 69, 549 A.2d 792, we held that a person who is convicted of serious-bodily-injury murder under N.J.S.A. 2C:11-3(a)(1) or (2) may not be *413sentenced to death. If the evidence provides a rational basis for a jury to convict a defendant of either intentional or serious-bodily-injury murder, the trial court “must instruct the jury to specify which, if [either], of those findings forms the basis for a conviction.” State v. Coyle, 119 N.J. 194, 209, 574 A.2d 951 (1990).
In arguing that there was no rational basis for a finding of serious-bodily-injury murder, the State points to the medical evidence suggesting that the victim had been hit fifteen times in the head with a blunt instrument and that her neck had been squeezed for an hour. The victim’s jaw was broken. Defendant confessed that he had hit her with a “hammer-like object.”
Of course, such repeated blows can support a jury finding of intentional murder. However, the issue here, as in other preGerald capital cases, is whether that was the jury’s determination. The jury was not asked to distinguish between intentional murder and serious-bodily-injury murder. Its verdict did not indicate which of the two it found to apply to this case. Although it might seem probable that the jury had intentional murder in mind, the question is whether there is a rational basis in the evidence on which the jury, if instructed to distinguish between the two, might return a verdict of serious-bodily-injury murder. If there is, then the jury, as the finder of fact, must decide the matter. An appellate court cannot.
The State conceded that defendant’s initial intent was to commit burglary, not murder. Defendant confessed that he had struck the victim only once, in response to being hit in the nose. That evidence suggests that defendant may have intended only to injure the victim, not to kill her. We note too that while arguing for purposes of the Gerald issue that the number of blows inflicted unquestionably establishes an intention to kill, the State claims for penalty-phase purposes that the first blows were intended to injure and inflict pain before death rather than to kill. See infra at 434, 581 A.2d at 496 (discussion of c(4)(c) aggravating factor).
*414The jury was free to reject the pathologist’s testimony and accept the other evidence that indicated a lack of murderous intent. See State v. Crisantos (Arriagas), 102 N.J. 265, 273, 508 A.2d 167 (1986) (a jury has “the power to disregard even overwhelming proof”). This was not merely a one-issue case requiring the jury to determine only whether defendant had in fact been the one who had inflicted the intentionally-fatal blows. The mental state of the perpetrator was also clearly in issue here. The trial court instructed the jury not just on capital murder, but also on felony-murder, aggravated manslaughter, and manslaughter. Obviously, then, the trial court believed the evidence would allow the jury rationally to convict on one of those counts while acquitting defendant on capital murder. A rational jury could have concluded that defendant inflicted the fatal blows but.had not intended to kill. The determination of whether defendant had the mens rea necessary to permit the State to put him to death is quintessentially one that our system of law entrusts to juries. All mental states related to the law of homicide were developed over a long period of history for the purpose of distinguishing capital murders from others. Wechsler & Michael, “A Rationale of the Law of Homicide I,” 37 Colum.L.Rev. 701 (1937). Determining a defendant’s mental state is the special function of the jury, not of this Court.
The record provided “a rational basis for the jury to find that the defendant intended to cause only serious bodily injury.” State v. Coyle, supra, 119 N.J. at 209, 574 A.2d 951. Because the trial court understandably failed to anticipate Gerald and did not instruct the jury to distinguish that offense from intentional murder, we reverse defendant’s capital-murder conviction.
Ill
We turn now to those alleged errors that might arise again at retrial.
*415—A—
Defendant argues that the trial court should have suppressed his confession. He claims that on five occasions he asserted his right to remain silent, but that the police did not “scrupulously honor” his invocations. See Michigan v. Mosley, 423 U.S. 96, 103-04, 96 S.Ct. 321, 326, 46 L.Ed.2d 313, 321 (1975). Defendant contends that the police violated the bright-line test adopted in State v. Hartley, 103 N.J. 252, 511 A.2d 80 (1986), by not re-informing him of his Miranda rights after each invocation of his right. He also alleges that his confession was not voluntary.
-1-
The police arrested defendant at about 7:30 a.m. on October 28, 1985. When they reached the station an hour later, the police read the Miranda warnings to defendant, who then signed a rights form. The police did not question him that morning.
At 3:37 that afternoon, Sergeant Hibbs and Detective Swan-hart began interrogating defendant. They again gave Miranda warnings to defendant, who signed another rights form. After eliciting personal information from defendant, the police started asking him about other crimes. At about 4:10 p.m. they questioned him about the Schnaps murder. Defendant denied responsibility, began to cry, and “asked for time to think, he wanted time by himself * * The questioning ceased and the police returned defendant to his cell. Forty minutes later the police brought defendant back to the interrogation room. On the way an officer “reminded” him of his rights but did not issue the formal Miranda warnings. When the police asked defendant about the Schnaps murder, he again began crying and said: “[BJefore I talk or say anything else I want to talk to my mother-in-law Pearl Thomas.”
Thomas arrived at the station an hour later and spoke with defendant for five minutes in his cell. At 7:30 p.m. the police took defendant back into the interrogation room. They gave *416him no Miranda warnings or reminders. When the police broached the Schnaps murder at 8:00 p.m., defendant again began to cry and said that he “just didn’t do anything.” According to one of the officers, the questioning then ended, “not at his request or our request, it was a mutual thing.” Defendant was returned to his cell.
Fifteen minutes later defendant asked to speak with Detective Swanhart alone. Swanhart “reminded” defendant of his rights and talked to him for an hour and a half. Defendant did not admit killing Irene Schnaps but he did confess to other crimes.
Around midnight a detective from the prosecutor’s office spoke to defendant about the murder. He orally advised defendant of his Miranda rights. The interview lasted only a couple of minutes, and defendant did not give a statement.
The next morning, October 29, two officers took defendant for a one-hour car ride to the scenes of the crimes he had admitted the night before. No Miranda warnings were given.
At defendant’s arraignment that day for offenses unrelated to the Schnaps murder, the municipal court did not ask him if he had or desired an attorney. That afternoon defendant was read his Miranda rights and signed a rights form. During the interrogation he consented to searches of his room and car. The search of the car turned up a Seiko LaSalle watch, later identified as having belonged to Schnaps’ deceased husband.
That night the police interviewed defendant in a holding room at the jail. After reading defendant his Miranda rights, the police told him that they had found the watch in his car. Defendant “responded as if talkin’ to himself, he said, oh, not in the car, he said no, no, not in the ear.” Defendant again denied involvement in the Schnaps murder.
The next day, October 30, defendant was arraigned in Superi- or Court for the murder of Schnaps. At about 10:00 that morning, after reissuing defendant his Miranda rights, the police started questioning him about the Schnaps murder. *417Shortly after 11:00 a.m., defendant informed the officers that “he would tell [them] about the murder but he first wanted to speak to his father.” Questioning ceased, and arrangements were made to transport defendant’s father to the jail. Defendant had lunch and talked to the officers about “things in general.” At 2:15 p.m. defendant went to the prosecutor’s office, where he spoke with his father for fifteen minutes before returning to jail.
At 2:30 p.m. the interrogation resumed without new Miranda warnings or reminders. Defendant confessed having killed Schnaps. The police took him back to the prosecutor’s office for a formal statement. When they read him his Miranda rights, defendant demanded an attorney. Questioning ceased.
—2—
Defendant claims that he asserted his right to silence four times on October 28, two days before his confession: at the 3:30 p.m. interrogation when he asked for “time to think * * * by himself”; at the 5:00 p.m. interrogation when he asked to speak to his mother-in-law; at 7:00 p.m. when he “asked for more time”; and at the 7:30 p.m. interrogation when he began to cry and said that he “just didn’t do anything.”
The only statement that defendant seeks to suppress is his confession of October 30. Because of the intervening events between the alleged invocations on October 28 and the confession, we need not decide whether defendant actually invoked his right to remain silent and whether the police scrupulously honored those alleged requests. Even if the police did not scrupulously honor defendant’s alleged invocations of his right to silence, the confession was “sufficiently independent to dissipate the taint of their illegal conduct.” State v. Johnson, 118 N.J. 639, 653, 573 A.2d 909 (1990).
The determination of whether a confession was the “fruit” of prior illegal police conduct involves three factors:
*418(1) the temporal proximity between the illegal conduct and the challenged evidence; (2) the presence of intervening circumstances; and (3) the flagrancy and purpose of the police misconduct. [Ibid.]
None of those factors helps defendant. First, his confession was not “temporally proximate” to the alleged violations — it occurred two days later — nor did it follow a prolonged illegal detention. See id. at 654-55, 573 A.2d 909 (repeated constitutional violations during illegal ten-hour detention preceded defendant’s escape).
Second, a number of intervening circumstances separated the alleged violations of October 28 from the confession. At 8:15 p.m. on October 28, after the fourth alleged invocation, defendant asked to speak with Detective Swanhart alone. Fresh Miranda warnings are not necessary if the accused initiates conversation after invoking the right to silence. State v. Fuller, 118 N.J. 75, 570 A.2d 429 (1990). Moreover, defendant was reminded of his rights at that time as well as later that evening. The next day he was arraigned before a municipal court judge. After receiving new Miranda warnings that afternoon, he signed a rights form. That evening he was read his rights again. The following day, October 30, he was arraigned a second time and received the Miranda warnings again.
Finally, there is no evidence of police coercion or misconduct. There were no extended interrogations designed to wear down defendant’s will. Even if defendant had invoked his right to remain silent on October 28, any possible taint from the police’s alleged failure scrupulously to honor his invocations was sufficiently dissipated.
The fifth time defendant allegedly invoked his right to remain silent was on October 30 when he asked to talk to his father. Although defendant indicated that he would talk about the Schnaps murder when questioning resumed, there was a significant break in the interrogation. Approximately three- and-one-half hours passed before the police resumed the inter*419rogation. But what makes the interruption significant is not its length so much as its nature. The request here was qualitatively different from the one in State v. Bey, 112 N.J. 123, 139, 548 A.2d 887 (1988) (Bey II), in which the defendant “requested permission to lay down and to think about what happened.” The Court likened that situation to one in which a defendant asks for “something to eat or drink, the use of toilet facilities, [or] the opportunity to stand and stretch * * Ibid. Defendant’s request here was not for a brief respite to satisfy physical needs. Instead he was asking, after three days in custody, for the chance to consult with a close family member.
Defendant’s request is similar to the one in State v. Hartley, supra, 103 N.J. at 258, 511 A.2d 80, in which the defendant told the police, “I don’t believe I want to make a statement at this time.” In both cases the defendant suggested that he would talk to the police later. “[A] request to terminate an interrogation must be honored ‘however ambiguous.’ ” State v. Bey, 112 N.J. 45, 64, 548 A.2d 846 (1988) (Bey I) (quoting State v. Kennedy, 97 N.J. 278, 288, 478 A.2d 723 (1984)). Certainly the request here was no more equivocal than the one in Bey I in which, according to the police, the defendant had “indicated he did not want to talk * * * about it * * Ibid. Defendant’s conduct during three days of interrogation and his refusal to answer questions about the Schnaps murder likewise indicated that he did not want “to talk about it.”
This case also resembles Law v. State, 21 Md.App. 13, 318 A.2d 859 (1974), in which the police were questioning the wounded defendant as he lay handcuffed to his hospital bed. The defendant told the police that “he didn’t want to talk any more until he was further treated.” Id. at 36, 318 A.2d at 872 (emphasis deleted). Despite his request, the police continued to question him. The court held that the defendant’s ensuing statement was inadmissible. Although the obvious difference from this case is that here defendant was not wounded, the court’s decision in Law rested on the defendant’s words, not on the surrounding circumstances. In both this case and Law, the *420defendants indicated that they would talk, but only after a subsequent condition had been met. In Law the condition was further treatment. Here the condition was a meeting with defendant’s father. The implied intent to talk later does not change the fact, as the court found in Law and as we find here, that defendant sought to terminate the interrogation.
The' importance of the police’s failure to reissue Miranda warnings after defendant had met his father is clearly shown by what happened when the police finally did give him the warnings. After defendant had confessed orally, the authorities gave him new Miranda warnings before seeking to take a formal statement. Deféndant immediately demanded an attorney before any statement could be reduced to writing. It is no stretch to imagine that defendant would have requested an attorney had the police given him warnings when they first interrogated him after he had met with his father.
The mandate of State v. Hartley, supra, 103 N.J. 252, 511 A.2d 80, is clear. When a defendant seeks to terminate an interrogation, the police must at a minimum give fresh Miranda warnings before recommencing questioning. Id. at 256, 511 A.2d 80. Any statement made prior to the new warnings must be suppressed. We pause to observe that although our dissenting colleague Justice Stein readily acknowledges that “defendant asserted his right to cut off questioning,” post at 444, 581 A.2d at 501, nevertheless he concludes — contrary to the unmistakable language of Hartley’s “bright line” rule, see 103 N.J. at 267, 511 A.2d 80 — that “the resumption of interrogation [thereafter] did not constitute a failure by the police to ‘scrupulously honor’ defendant’s right to remain silent.” Post at 444, 581 A.2d at 501. Either defendant exercised his right (as we and Justice Stein conclude), or he did not (as Justice O’Hern concludes). If he did, then without question Hartley requires the readministering of Miranda warnings before the resumption of interrogation.
*421We apply the Hartley rule even though that rule was announced after the interrogation in this case had occurred. Retroactivity is not a consideration here. “The threshold question in any retroactivity decision is whether a new rule of law has actually been announced.” State v. Burstein, 85 N.J. 394, 403, 427 A.2d 525 (1981). The issue of retroactivity “never arises absent a new rule of law * * *.” State v. Lark, 117 N.J. 331, 344, 567 A.2d 197 (1989) (Clifford, J., concurring in judgment).
Hartley did not announce a new rule of law. It was “not a clear break with the past, but a simple extension of the principle of cases * * * holding that the State must honor ‘a defendant’s request — however ambiguous — to terminate interrogation.’ ” Bey II, supra, 112 N.J. at 213, 548 A.2d 887 (Handler, J., dissenting) (quoting State v. Kennedy, 97 N.J. 278, 288, 478 A.2d 723 (1984)). We said that our rule in Hartley was “sound as a matter of New Jersey common law [and] consistent with the spirit of the Supreme Court’s decisions * * State v. Hartley, supra, 103 N.J. at 268, 511 A.2d 80. The foundation of our decision was Michigan v. Mosley, supra, 423 U.S. 96, 96 S.Ct. 321, 46 L.Ed.2d 313, in which the Supreme Court held that the police had “scrupulously honored” the defendant’s decision to remain silent because they did not approach him for two hours, they gave him fresh Miranda warnings, a different officer questioned him, and the questioning concerned a different offense from the one for which he was in custody. Although the Supreme Court did not indicate which of those elements are essential for a finding that the police “scrupulously honored” a suspect’s rights, we held that the furnishing of fresh Miranda warnings is “indispensable.” State v. Hartley, supra, 103 N.J. at 267, 511 A.2d 80.
In reaching that conclusion, we relied on the decisions of other courts as well as academic literature. See, e.g., Wilson v. United States, 444 A.2d 25, 31 (D.C.1982) (all Mosley factors are required to validate reinterrogation); People v. Young, 115 Ill.App.3d 455, 71 Ill.Dec. 259, 450 N.E.2d 947 (1983) (recess *422and fresh Miranda warnings are a minimum prerequisite to reinterrogation); Kamisar, “The Edwards and Bradshaw Cases: The Court Giveth and the Court Taketh Away,” 5 The Supreme Court: Trends and Developments 1982-83 153 (1984) (fresh Miranda warnings are necessary for renewing questioning after suspect has indicated desire to remain silent).
Because Hartley did not announce a new rule of law, retroactivity is not an issue. Any defendant who had not exhausted direct appeals when Hartley was decided could have asserted a claim based on that opinion. Because the police did not give defendant fresh Miranda warnings after he had indicated his desire to remain silent, Hartley requires that the ensuing confession be suppressed.
Moreover, even if Hartley did create a new rule of law, it would still apply here under either the Supreme Court’s old analysis of retroactivity of new criminal procedure rules or its more recent pronouncement on retroactivity in Griffith v. Kentucky, 479 U.S. 314, 107 S.Ct. 708, 93 L.Ed.2d 649 (1987). Under its former analysis, the Supreme Court held that Miranda itself applies to interrogations that took place before that rule was announced if the trial did not commence until after the Miranda decision (precisely the sequence in this case), see Michigan v. Tucker, 417 U.S. 433, 447, 94 S.Ct. 2357, 2365, 41 L.Ed.2d 182, 195 (1974), but not if the case was tried before that decision, Johnson v. New Jersey, 384 U.S. 719, 733, 86 S.Ct. 1772, 1781, 16 L.Ed.2d 882, 892 (1966). The obvious similarity between the nature and effect of Miranda and Hartley suggests that the application of Hartley should be no less broad.
Turning to the Supreme Court’s most recent retroactivity pronouncements, we note first that Justice Stein correctly points out, post at 439, 581 A.2d at 499, that “ ‘[t]o the extent that retroactivity issues arise in the context of criminal-procedure decisions implicating rights guaranteed under the federal constitution, United States Supreme Court precedents control *423the scope of retroactivity,’ ” (citing State v. Lark, supra, 117 N.J. at 335, 567 A.2d 197 (1989), and that under Griffith v. Kentucky, 479 U.S. 314, 107 S.Ct. 708, 93 L.Ed.2d 649 (1987), “a new rule for the conduct of criminal prosecutions is to be applied retroactively to all cases, state or federal, pending on direct review or not yet final, with no exception for cases in which the new rule constitutes a ‘clear break’ with the past.” 479 U.S. at 328, 107 S.Ct. at 716, 93 L.Ed.2d at 661; see State v. Stever, 107 N.J. 543, 548-53, 527 A.2d 408 (1987) (discussing Supreme Court’s development of retroactivity principles). Clearly, then, Griffith mandates adherence to a Hartley analysis in this case. Justice Stein would avoid application of Griffith’s sound principle, however, on the ground that Hartley was not based “primarily” on federal-constitutional law, post at 425, 581 A.2d 491. Whatever “primarily” means in the foregoing context, our distinguished colleague is quite wrong.
First, it is abundantly clear that Hartley was grounded at least as much on the fifth amendment to the United States Constitution as it was on New Jersey’s common-law privilege, codified in our Evidence Rules. No fewer than sixteen times does the opinion refer specifically to its “constitutional” basis. For example, we emphasized at the outset of Hartley that our decision was founded not only on state law but “on our understanding of the United States Supreme Court precedents in this area.” State v. Hartley, supra, 103 N.J. at 256, 511 A.2d 80. And: “[T]he failure to readminister Miranda warnings was a violation of the obligation scrupulously to honor Hartley’s asserted right to silence, and therefore amounted to a violation of defendant’s fifth-amendment and state common-law right not to be compelled to be a witness against himself.” Id. at 278, 511 A.2d 80. And: any statement obtained in violation of Hartley’s “bright-line” rule is “unconstitutionally compelled, and hence inadmissible, as having been obtained in violation of the fifth amendment and of the state common-law right against self-incrimination.” Id. at 279, 511 A.2d 80. And finally: “[T]he failure scrupulously to honor Hartley’s previously-in-*424yoked right to silence was a violation of constitutional magnitude * * *.” Id. at 283, 511 A.2d 80.
Second, one need look no further than Justice Stein’s own opinion for the Court in Bey I, supra, 112 N.J. 45, 548 A.2d 846, for confirmation of the federal-constitutional basis of Hartley: “As in Hartley * * * we base our analysis [of whether the police had scrupulously honored Bey’s right to cut off questioning] on both federal constitutional law and our State common-law privilege against self-incrimination.” Id. at 63, 548 A.2d 846 (citing Hartley, supra, 103 N.J. at 284, 511 A.2d 80). And: “Hartley held that where the failure scrupulously to honor a suspect’s right to cut off questioning results from the absence of fresh Miranda warnings before resuming questioning, the illegality renders the suspect’s subsequent inculpatory statement unconstitutionally compelled as a matter of law.” Id. at 71, 548 A.2d 846 (emphasis added).
Note too that in Bey the interrogation occurred in May 1983 and the trial court heard the motion to suppress Bey’s confession late in that same year. This Court decided Hartley in July 1986 and Bey I more than two years later, in August 1988. In Bey I we simply applied Hartley to a case that had been on direct appeal when Hartley was decided. See id. at 58-74, 548 A.2d 846. Likewise, in Bey II, supra, 112 N.J. 123, 548 A.2d 887, this Court engaged in a full discussion of the Hartley principle, see id. at 134-43, 548 A.2d 887, prompting two dissents on the issue of the admissibility of the defendant’s confession under a Hartley analysis, see id. at 184-88, 548 A.2d 887. There was no necessity to discuss or rule on any question of Hartley’s retroactivity, because the Court assumed, again correctly, its applicability. No more was it an issue there than it is here. And if Hartley applied in the Bey cases, on appeal when Hartley was decided, a fortiori it applies when, as here, the trial began after the Hartley opinion had been published.
*425Finally, Justice Stein overestimates Hartley’s impact (“a multitude of post-conviction-relief applications,” post at 442, 581 A.2d at 500), on cases such as this, which were tried after Hartley had been decided. Griffith would limit retroactive application to cases “in the pipeline” — those on appeal when Hartley was decided, in which the Hartley point had been raised — and would not affect cases that had gone to final decision before Hartley. We suspect the number is minimal; and in any event the burden is not more than the criminal-justice system should be asked to bear.
We hold that the Hartley rule bars the introduction of defendant’s confession at retrial. We need not consider defendant’s claim that his confession was involuntary.
—B—
Defendant objects to two statements made by the prosecutor during his opening. After describing the murder of Schnaps, the prosecutor told the jury:
So, as you can see, this is a very important trial. It’s important for Nathaniel Harvey. It’s important for the family of the victim, and it’s important to each and every citizen.
Later the prosecutor observed that Schnaps “was a recent widow, her husband having died six weeks * * * previously.”
The prosecutor’s comments were improper. They drew attention not to issues relevant to the crime charged but to the status of the victim and her family. His reference to her recent widowhood was “plainly designed to impassion the jury” and “ ‘contained] nothing that would aid the jury in determining the defendant’s guilt or innocence.’ ” State v. Hightower, 120 N.J. 378, 411, 577 A.2d 99 (1990) (quoting State v. Williams, 113 N.J. 393, 452, 550 A.2d 1172 (1988)). On retrial the prosecutor must refrain from making such comments.
—C—
Defendant makes several objections to the testimony of four of the State’s expert witnesses.
*426—1—
First, defendant argues that the trial court should not have qualified Dr. Claude Owen Lovejoy as an expert to testify about the bloody sneaker print found on the pillowcase. Dr. Lovejoy, a professor at Kent State University, received a doctorate in biological anthropology, which according to him is “the study of human form and function, evolution of the human species, human variation involving anatomy, genetics, essentially the normal biology of man.” His specialty is “the form and function and biomechanics of the lower limb.” He claims to be able to estimate the stature of a person from the size of his or her shoes.
In October 1985 the police sent Dr. Lovejoy four photographs of the pillowcase containing a sneaker print. After having examined the pictures, Dr. Lovejoy concluded that the bloody print had been left by either a male of “short stature” or a female of “average to medium tall stature.” The police then sent Dr. Lovejoy the actual pillowcase and three pairs of Pony hightop sneakers, marked in evidence as S-58, S-59, and S-60, two of which they said belonged to defendant’s son. The professor immediately decided that neither S-59 nor S-60 had left the print, but he was unsure about S-58. He then made a print with S-58 on a pillowcase stuffed with a pillow. Comparing that print to the one on Schnaps’ pillowcase, Dr. Lovejoy concluded that it was “improbable” that S-58 had left the print.
The Pony Sneaker Company sent Dr. Lovejoy thirty-one pairs of sneakers from the same manufacturing run as S-58. The sneakers ranged in size from 7 to 11; none was 6, 6V2, or 7V2. The doctor took three measurements of the sole of each sneaker and plugged them into his “digitizer” to determine the size of the shoe that had left the print:
Okay, what we did was we took * * * each of the individual shoes in the Pony sample, measured each of the dimensions that I’ve just talked about, put those into a data base, into a computer, along with shoe size and determined the relationship between those using a variety of statistical techniques.
*427The simplest of those is called linear correlation and if one puts a set of dimensions, two sets of dimensions from the same object into the computer it will determine the degree of relationship between them, it will give you for example, the ability of one metric to predict the other with certain limits of reliability and that’s what we mean by correlation and the strength of that physical relationship is expressed as varying from minus one through zero to plus one plus one being a perfect positive relationship, minus one being a perfect negative relationship.
Based on that analysis, Dr. Lovejoy concluded that the sneaker that had made the print was either a man’s size 6V2, plus or minus one-half size, or a woman’s size 8 to 8V2. The confidence limit of that conclusion was 95%, i.e., the conclusion would be accurate within a one-half size 95% of the time. Deciding that hightop and lowtop sneakers have decorative stripes on different portions of the outer sole, he concluded that the sneaker was a hightop.
There are three requirements for the admission of expert testimony:
(1) the intended testimony must concern a subject matter that is beyond the ken of the average juror; (2) the field testified to must be at a state of the art such that an expert’s testimony could be sufficiently reliable; and (3) the witness must have sufficient expertise to offer the intended testimony.
[State v. Kelly, 97 N.J. 178, 208, 478 A.2d 364 (1984).]
Comparison between a shoe print and the shoe alleged to have made that print does not require expert testimony. State v. Johnson, 120 N.J. 263, 293-94, 576 A.2d 834 (1990). Nor is the proposition that shorter people tend to have smaller feet the stuff of expert testimony. It would be improper to use Dr. Lovejoy’s professed expertise to bolster such testimony. However, to the extent that Dr. Lovejoy sought to establish with scientific reliability the size of the shoe and the height of the person that left the print, expert testimony was proper.
Concerning the second requirement for the admission of Dr. Lovejoy’s expert testimony, there are three ways, in a relatively new field of research, to prove the evidence’s “general acceptance and thereby its reliability”:
(1) by expert testimony as to the general acceptance, among those in the profession, of the premises on which the proffered expert witness based his or her analysis; (2) by authoritative scientific and legal writings indicating that the *428scientific community accepts the premises underlying the proffered testimony; and (3) by-judicial opinions that indicate the expert’s premises have gained general acceptance. [State v. Kelly, supra, 97 N.J. at 210, 478 A.2d 364.]
The State did not satisfy either the first or second alternative. It did not provide evidence that anyone in the scientific community other than Dr. Lovejoy himself vouches for his methods.
Nor do judicial opinions indicate that Dr. Lovejoy’s methods have gained general acceptance. In State v. Prudden, 212 N.J.Super. 608, 515 A.2d 1260 (App.Div.1986), the same trial court that presided over these proceedings had qualified Dr. Lovejoy as an expert to testify about a sock print. Reversing on other grounds, the Appellate Division expressed reservations about the reliability of Dr. Lovejoy’s methods. Id. at 617-18, 515 A.2d 1260. Dr. Lovejoy also testified in United States v. Ferri, 778 F.2d 985 (3d Cir.1985), cert. denied, 476 U.S. 1172, 106 S.Ct. 2896, 90 L.Ed.2d 983 (1986), to rebut the testimony of the government’s footprint expert, who had compared one defendant’s footprints with impressions inside shoes found at the crime scene and inside shoes seized from the defendants’ residences. Notwithstanding Prudden and Ferri, we are unaware of any cases in which an expert’s testimony involved the scientific comparison of sneaker prints with stature.
We also note several glaring weaknesses that east doubt on the reliability of Dr. Lovejoy's conclusions. He admitted that he knew nothing about sneaker manufacturing or about the extent of variations from manufacturer to manufacturer or plant to plant. According to defendant, a Pony representative reported that the sneaker print had not even been made by a Pony. In conducting his analysis, Dr. Lovejoy used sneakers only from the same production series as that of S-58. Yet he had already determined that S-58 had not made the print. Nor was there any showing that the thirty-one pairs he measured were representative of the production run. Moreover, although he concluded within a 95% confidence limit that the shoe that *429had left the print was size 6V2, every shoe he examined from that production run was at least a size 7.
Because Dr. Lovejoy’s methodology was not of sufficient scientific reliability, we need not consider the third requirement of whether he had sufficient expertise in the field. On retrial Dr. Lovejoy may not testify as an expert.
—2—
Theodore Mozer, a forensic chemist, testified as an expert on hair comparison. Mozer has worked for the New Jersey State Police for over fifteen years as a principal forensic chemist specializing in the analysis of human hairs in assault and homicide cases. He received a B.S. in biology and took graduate courses in chemistry. Mozer also took courses in the microscopy of human hair at the F.B.I. Academy in Virginia. A member of the International Committee on Hair Comparison, Mozer has examined hair samples in over 1,000 criminal cases and has testified as an expert in hair comparison between fifty and one-hundred times.
After analyzing seventy-five hairs found at the murder scene, Mozer determined that one of them was a black person’s pubic hair that did not match Schnaps’ hair. Comparing a hair sample from defendant, Mozer concluded that the hair had come either from defendant or from “[a]nother individual who had [the] same microscopic characteristics.”
According to defendant, Mozer was not qualified on that subject because he was unfamiliar with a purported standard in the science of hair comparison that an expert must find fifteen to twenty similar characteristics before an opinion can be deemed reliable. See, e.g., People v. Allweiss, 48 N.Y.2d 40, 49, 421 N.Y.S.2d 341, 346, 396 N.E.2d 735, 740 (1979), and People v. Watkins, 78 Mich.App. 89, 93-96, 259 N.W.2d 381, 384-85 (1977). At the Rule 8 hearing, Mozer admitted that he was unaware of such a standard but explained that the technique he used included analyzing “hundreds of different characteristics of these two hairs side by side and seeing whether or not they *430compare.” Given Mozer’s extensive experience in hair comparison, as established at the Rule 8 hearing, the trial court did not abuse its discretion in admitting him as an expert.
Defendant also claims that the State should not have been allowed to refer to the hair as a “pubic hair” because it conjures images of a sexual assault. We agree that the fact that the hair is a pubic hair is not relevant in this case. The important fact is that the hair might have come from defendant. Whether it might have come from his head, his chest, or his pubis is irrelevant in the absence of allegations of a sexual encounter. On retrial the prosecution should refrain from referring to the hair as a “pubic hair.”
—3—
Defendant challenges the trial court’s ruling that Philip Beesley was qualified to render an opinion regarding the percentage of blacks with a certain genetic marker in their blood. Beesley, an expert in forensic serology, analyzed four blood stains from Sehnaps’ apartment that did not match the victim’s blood but did match defendant’s. He found that the four stains and a sample of defendant’s blood all contained enzyme CAII, which is present only in blacks. Beesley testified that only 17.5% of the black population have CAII.
Defendant contends that Beesley was unqualified to testify about the percentage of the population that has CAII. In reaching that figure, Beesley relied in part on a State study of 337 blood samples taken from blacks. The study concluded that 17.5% of the black population in New Jersey have CAII. Beesley had not participated in that study and did not know how it had been conducted. Nor has that study ever been published and subjected to scientific scrutiny. His only basis for vouching for the study’s reliability was that “[t]he person who did perform all that analysis and all that data knows a lot about statistics * * *.” The in-house study was an insufficient ground for Beesley to testify about the 17.5% figure.
*431Beesley, however, also relied on the Source Book of Forensic Serology, which states that CAII exists in 17.5% of blacks. If on retrial the State can show that that book and figure are considered authoritative in the forensic-serology community, it can introduce the figure through Beesley. See Evid.R. 56(2); Mauro v. Owens-Corning Fiberglas, 225 N.J.Super. 196, 206, 542 A.2d 16 (App.Div.1988) (expert could testify about statistical data “ ‘of a type reasonably relied upon by experts’ in the field of pulmonary disorder”), aff'd sub nom. Mauro v. Raymark Indus., 116 N.J. 126, 561 A.2d 257 (1989).
Defendant also claims that the jury’s consideration of statistical evidence quantified reasonable doubt and usurped its function of weighing the evidence. The argument is without merit. See State v. King, 215 N.J.Super. 504, 520, 522 A.2d 455 (App.Div.1987) (“[s]imply because [a] figure is rather high is no reason to exclude it if the test procedure is a valid one”).
—4—
Defendant contends that Dr. Shuster, who had conducted the autopsy of the victim, improperly testified about opinions that were not based on a reasonable degree of medical certainty or probability. For example, Dr. Shuster testified that the skull injury was “possibly” two wounds or “possibly not.” We need not delve into each part of Dr. Shuster’s testimony. We merely instruct the trial court that on remand Dr. Shuster’s ultimate “[m]edical expert testimony ‘must be couched in terms of reasonable medical certainty or probability; opinions as to possibility are inadmissible.’ ” State v. Freeman, 223 N.J.Super. 92, 116, 538 A.2d 371 (App.Div.1988) (quoting Johnesee v. Stop & Shop Co., 174 N.J.Super. 426, 431, 416 A.2d 956 (App.Div.1980)).
—D—
The trial court conducted a hearing to determine whether the State could impeach defendant’s credibility with a prior *432conviction. The hearing centered on defendant’s 1979 four-count conviction arising from a rape. Defendant was sentenced to a prison term of fifteen to twenty years. The record does not indicate when he was released. The trial court allowed the State to use the conviction for impeachment.
“The well-established rule in this jurisdiction is that admission of a prior conviction ‘into evidence against a criminal defendant rests within the sound discretion of the trial judge.’ ” State v. Pennington, 119 N.J. 547, 586, 575 A.2d 816 (1990) (quoting State v. Sands, 76 N.J. 127, 144, 386 A.2d 378 (1978)). The defendant has the burden of showing that the conviction should be excluded. Ibid. “The key to exclusion is remoteness.” State v. Sands, supra, 76 N.J. at 144, 386 A.2d 378.
The trial court here did not abuse its discretion in permitting the use of defendant’s conviction for impeachment purposes. The conviction was only seven years old. Moreover, because defendant had been sentenced to a prison term of fifteen to twenty years, at the time of trial he must have been out of prison for less than seven years. Given the seriousness of his prior offenses, we see no reason to second-guess the trial court.
—E—
Defendant contends that the trial court improperly admitted sixty color photographs of the murder scene and of the victim’s body. We do not rule on that challenge here but alert the trial court on remand to the standards set forth in State v. Thompson, 59 N.J. 396, 283 A.2d 513 (1971), and discussed in State v. Johnson, supra, 120 N.J. at 296-299, 576 A.2d 834, State v. Moore, 113 N.J. 239, 295-97, 550 A.2d 117 (1988), State v. Rose, 112 N.J. 454, 533-36, 548 A.2d 1058 (1988), and Bey II, supra, 112 N.J. at 181-83, 548 A.2d 846.
—F—
Peggy Stevens testified that someone had stolen perfume and a camera from her house about a week before the *433murder of Schnaps. Several months later she had reported that a hatchet had been stolen. Because her family had used the hatchet only during the fall and winter, she did not know how long it had been missing. When the police searched defendant’s car, they found the camera and undeveloped photographs of Stevens’ family.
At a Rule 8 hearing the State argued that Stevens’ testimony established defendant’s identity, showed his intent, and corroborated his confession, in which he had admitted having stolen a “hammer-like” instrument from someone’s garage a week before the murder. Defendant countered that Stevens’ testimony was inadmissible “other crimes” evidence because she could not state when she had last seen the hatchet and because her testimony did not prove that defendant had stolen it.
Evidence of “other crimes” is not admissible to prove a person’s disposition to commit crime but is admissible “to prove some other fact in issue including motive, intent, plan, knowledge, identity, or absence of mistake or accident.” Evid.R. 55. The State bears the burden of proving other crimes by clear and convincing evidence. State v. Stevens, 222 N.J.Super. 602, 614, 537 A.2d 774 (App.Div.1988), aff'd, 115 N.J. 289, 558 A.2d 833 (1989).
Although the trial court admitted the evidence at first for “the issues of identification, state of mind, purposefully or knowingly, type of instrument used, presence of the defendant at the scene, [and] corroboration of [defendant’s] confession,” its jury instructions limited consideration of the evidence to the issue of identification.
Defendant argues that the testimony was inadmissible at the guilt phase because the State did not prove by clear and convincing evidence that defendant had stolen the items. The State, however, did provide substantial evidence of that allegation. The Stevens family had reported their camera as stolen about a week before the murder. The police had found the camera and film in the trunk of defendant’s car. Defendant *434had confessed to having stolen a “hammer-like” object from a garage shortly before Schnaps’ death. The trial court did not abuse its discretion in allowing Stevens' testimony. However, because we have determined that defendant’s confession must be suppressed, the trial court should reconsider the issue in light of the remaining evidence.
The State contends that the trial court should have allowed the jury to consider Stevens’ testimony not only for identification but also as evidence of defendant’s purposeful intent. We see no basis for finding that the trial court abused its discretion in limiting admissibility to the issue of identification.
Defendant also argues that even if Stevens’ testimony is admissible at the guilt phase, it should not be admitted at the penalty phase. In the penalty phase the State “is restricted to proving the statutory aggravating factors and rebutting proof of mitigating factors.” State v. Rose, supra, 112 N.J at 503, 548 A.2d 1058. The State asserts that Stevens’ testimony is relevant to aggravating factor c(4)(c) as showing that “defendant armed himself with a weapon capable of inflicting pain and suffering in addition to death.” The testimony is not admissible at the penalty phase for that purpose. The fact that defendant may have stolen a hatchet from the Stevenses is not relevant to c(4)(c). What matters is whether he used that weapon to inflict pain and suffering on the victim. Stevens’ testimony is not relevant to that question. However, her testimony might be relevant to the issue of intent under c(4)(c). If the State proposes to show that defendant stole the hatchet for the purpose of inflicting pain and suffering on a future murder victim, Stevens’ testimony might be admissible. Otherwise, if defendant is convicted of capital murder on remand, the trial court should not admit her testimony at the penalty phase.
—G—
Defendant alleges a number of penalty-phase errors involving jury instructions that did not conform to our holdings in *435subsequent capital cases. We need not consider those claims now. If there is a new penalty phase on remand, the trial court should heed those opinions in formulating its instructions.
Defendant also contends that the evidence does not support a finding of aggravating circumstance c(4)(c), that the murder was wantonly vile, horrible, or inhumane. The State argues that the murder of Schnaps falls into the category of c(4)(c) murders in which the perpetrator “intended to cause, and did in fact cause, severe physical or psychological pain or suffering to the victim prior to the victim’s death.” State v. Ramseur, 106 N.J. 123, 211, 524 A.2d 188 (1987). The State claims that defendant initially struck Schnaps in the head with the hatchet to cause her severe physical pain and suffering prior to her death. Only later did he strike the fatal blows. The State further argues that there was evidence of post-death mutilation of the body that indicates depravity of mind.
Because the trial occurred before our opinion in Ramseur, the trial court did not analyze the evidence under our narrowed construction of c(4)(c). Given the factual nature of that issue, we will not pass on it without the trial court’s having had the opportunity to evaluate the evidence. See State v. Hightower supra, 120 N.J. at 420, 577 A.2d 99.
—IY—
Defendant’s capital-murder conviction is reversed. The cause is remanded for a new trial.