Reversed in part and affirmed in part by published opinion. Judge LUTTIG wrote the majority opinion, in which Judge WILLIAMS joined. Judge MURNAGHAN wrote an opinion concurring in the judgment.
OPINION
LUTTIG, Circuit Judge:The United States District Court for the Eastern District of Virginia vacated the death sentence of habeas corpus petitioner Herman Barnes, holding that the Commonwealth withheld exculpatory evidence in contravention of Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963) and United States v. Bagley, 473 U.S. 667, 105 S.Ct. 3375, 87 L.Ed.2d 481 (1985), and that petitioner had shown cause for his failure to present timely his exculpatory-evidence claim in the courts of the Commonwealth of Virginia. Because the record clearly supports the Virginia Supreme Court’s determination that the information upon which the exculpatory-evidence claim was predicated was either known or reasonably available to petitioner, we reverse the district court’s judgment granting the writ of habeas corpus.
*973I.
Barnes planned to rob Bon’s Supermarket with the help of an accomplice, James Corey, on June 27, 1985. At approximately 10 p.m., Barnes approached Ricky Adams, a supermarket employee who was sweeping the parking lot, and pushed a pistol in his side. Using Adams as a shield, Barnes entered the store. Clyde Jenkins, the store’s seventy-three-year-old owner, engaged Barnes in a struggle at the front of the store and Barnes shot Jenkins twice. Another store employee, Mohammed Afifi, came from the back of the store and jumped on Barnes. Barnes shook Afifi off, shot and killed him. Barnes then turned and pointed the gun at Adams. At that moment, Jenkins stirred and attempted to rise from the floor. Barnes shot Jenkins a third time and fled. Although Jenkins survived two weeks in the hospital, he too ultimately died from the gunshot wounds.
A handgun belonging to Jenkins was found under or near him when the police arrived. It had not been fired. Barnes has never asserted, nor does he today, that he saw this gun.
Barnes was tried in a bench trial in July 1986 in the Circuit Court for the City of Hampton. At trial, the victim’s gun was admitted into evidence. The exact location where the police found the gun was never drawn into question and there was no testimony as to the location of the gun. The court convicted Barnes on five counts, including capital murder. In September of 1986, upon finding beyond a reasonable doubt that Barnes’ “conduct in committing the offense was outrageously and wantonly vile ... in that it did involve an aggravated battery to the victim,” the court sentenced Barnes to death. See J.A. at 124; Va.Code Ann. § 19.2-264.2. The Virginia Supreme Court affirmed his convictions and sentence on September 4, 1987, Barnes v. Commonwealth, 234 Va. 130, 360 S.E.2d 196 (1987), and the United States Supreme Court thereafter denied certiorari, 484 U.S. 1036, 108 S.Ct. 763, 98 L.Ed.2d 779 (1988).
In October 1988, Barnes filed a petition for writ of habeas corpus in the Circuit Court in Hampton, raising numerous challenges to his convictions and sentence. The Circuit Court dismissed the petition, J.A. at 146-47, and the Virginia Supreme Court refused the petition for appeal, J.A. at 178. The United States Supreme Court again denied certiorari. Barnes v. Thompson, 497 U.S. 1011, 110 S.Ct. 3257, 111 L.Ed.2d 766 (1990).
On November 19, 1990, Barnes filed a habeas petition in federal court. He raised the same issues he had raised in the state petition and, in addition, claimed for the first time that the Commonwealth’s failure to disclose the exact location of the victim’s gun violated his right to due process under Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963), and United States v. Bagley, 473 U.S. 667, 105 S.Ct. 3375, 87 L.Ed.2d 481 (1985), rendering his conviction and death sentence invalid. In June 1991, petitioner moved for, and was granted, a voluntary dismissal of his petition.
Barnes then filed a second state habeas petition in the Virginia Supreme Court, raising the exculpatory-evidence claims. J.A. at 179-204. The state court dismissed the petition “on grounds that no writ shall be granted on the basis of any allegation the facts of which the petitioner had knowledge at the time of filing of any previous petition. Code § 8.01-654(B)(2).” J.A. at 213.
In February 1992, Barnes filed a second federal habeas petition. In a memorandum opinion dated July 14, 1992, the district court dismissed seven of the ten assignments of error, but directed that an evidentiary hearing be conducted on Barnes’ claims that the Commonwealth’s failure to disclose the precise location of the gun violated Barnes’ due process rights, that the death penalty was improperly imposed if the victim was armed, and that Barnes was denied effective assistance of counsel. JA. at 294-332.
On January 18, 1994, following a two-day hearing, the district court held that the Commonwealth had violated Barnes’ due process rights by withholding the gun’s precise location and that the suppression of this evidence, although not sufficient to undermine confidence in Barnes’ capital-murder conviction, was sufficiently material that the death sentence had to be vacated. Specifically, the court concluded that if the petitioner had had *974the undisclosed information for use during the penalty phase of his capital trial, the sentencing court might not have found that Barnes committed an aggravated battery, and thus might not have found the “vileness” aggravating factor.1 The district court also found that Barnes was not denied effective assistance of counsel. J.A. at 673-96.
II.
The Commonwealth argues on appeal that the district court erred in finding that Barnes was not procedurally barred from raising the Bagley claim in his federal habeas petition, given that he defaulted this claim pursuant to Virginia Code section 8.01-654(B)(2).
Under Wainwright v. Sykes, 433 U.S. 72, 97 S.Ct. 2497, 53 L.Ed.2d 594 (1977), and succeeding cases, if a state prisoner has defaulted his federal claims in state court pursuant to an independent and adequate state procedural rule, he is barred from raising those claims on federal collateral review unless he can show cause for the default and prejudice resulting therefrom. Id. at 87-91, 97 S.Ct. at 2506-09; Coleman v. Thompson, 501 U.S. 722, 750, 111 S.Ct. 2546, 2565, 115 L.Ed.2d 640 (1991).2 The district court properly recognized that the Supreme Court of Virginia “explicitly relied upon [the] procedural bar” of Virginia Code section 8.01-654(B)(2) to dismiss the claim. J.A. at 692. The court held, however, that Barnes showed both cause and prejudice for his- failure to raise the claim. In both of these determinations, we believe the district court erred.
A.
Under our precedents, inherent in the state court’s determination that Barnes’ Bagley claim was procedurally barred under section 8.01-654(B)(2) is a finding that no external factor existed to excuse Barnes’ failure to present this claim in his first state habeas petition. See Clanton v. Muncy, 845 F.2d 1238, 1241 (4th Cir.), cert. denied, 485 U.S. 1000, 108 S.Ct. 1459, 99 L.Ed.2d 690 (1988). That is, the section 8.01-654(B)(2) default determination by the Commonwealth’s highest court reflects a finding that “all of the facts on which the current petition was based were either known or available to the petitioner.” Waye v. Murray, 884 F.2d 765, 766 (4th Cir.), cert. denied, 492 U.S. 936, 110 S.Ct. 29, 106 L.Ed.2d 634 (1989). This factual finding is entitled to a presumption of correctness on federal habeas review, Clanton, 845 F.2d at 1241; Waye, 884 F.2d at 766 (section 8.01-654(B)(2) decision is “entitled to presumptive validity under 28 U.S.C. *975§ 2254(d)”),3 and may be rebutted only if the finding is “not fairly supported by the record,” 28 U.S.C. § 2254(d)(8). See also Stockton v. Murray, 41 F.3d 920, 924-25 (4th Cir.1994). In reaching its determination that petitioner had shown cause to excuse his failure to raise timely the Bagley claim, the district court undertook its own cause inquiry de novo, rather than address whether the record supported the Virginia court’s factual determination that no cause existed for the delay in presenting this claim. Indeed, the district court never mentioned the presumptive validity of the state court’s finding that the facts underlying Barnes’ claim were either known or available to Barnes before he filed his first state habeas petition. Had the district court undertaken the proper inquiry, according the state court findings the required deference, it would have been apparent that the record fully supports the Virginia Supreme Court’s conclusion.
Assuming arguendo that the location of the gun was material, the governing question for the state court was whether Barnes could have obtained the information through “reasonable and diligent investigation.” McCleskey v. Zant, 499 U.S. 467, 498, 111 S.Ct. 1454, 1472, 113 L.Ed.2d 517 (1991). “The question is whether petitioner possessed, or by reasonable means could have obtained, a sufficient basis to allege a claim in the first petition....” Id. See also Stockton, 41 F.3d at 925 (“Even if [the petitioner] had not actually raised or known of the[ ] claims previously, he still cannot establish cause to excuse his default if he should have known of such claims through the exercise of reasonable diligence.”); United States v. Wilson, 901 F.2d 378, 380, 381 (4th Cir.1990) (Murnaghan, J.) (“ ‘[T]he Brady rule does not apply if the evidence in question is available to the defendant from other sources.’ ... [W]here the exculpatory information is not only available to the defendant but also lies in a source where a reasonable defendant would have looked, a defendant is not entitled to the benefit of the Brady doctrine.” (citation omitted)).4 The question was not, as the district court erroneously presumed, simply whether “the factual basis for petitioner’s claim was reasonably unknown to petitioner’s lawyers, in part because of ‘some interference by officials.’ ” J.A. at 693 (quoting Amadeo v. Zant, 486 U.S. 214, 222, 108 S.Ct. 1771, 1776, 100 L.Ed.2d 249 (1988) and Murray v. Carrier, 477 U.S. 478, 488, 106 *976S.Ct. 2639, 2645, 91 L.Ed.2d 397 (1986)). Even assuming “some interference by officials” (of which there is no evidence here other than the mere fact that the information was not produced), a petitioner still cannot show cause if the information sought is otherwise reasonably available. As the Court stated in Carrier, the official interference must have made “compliance [with the state’s procedural rule] impracticable.” 477 U.S. at 488, 106 S.Ct. at 2645.
Barnes, of course, knew from the inception of this case that the police recovered Jenkins’ gun from the store on the night of the murders. At the preliminary hearing, Mr. El-Amin, Barnes’ counsel, questioned a detective regarding the victim’s revolver, and was told that the gun “was recovered at the scene, shortly after the incident occurred.”5 J.A. at 299-300. Mr. El-Amin even asked the detective whether the gun had been fired. J.A. at 300. Mr. El-Amin and the Commonwealth’s attorney thereafter entered into a trial stipulation which stated:
A .38 caliber Smith & Wesson revolver serial number 204J49, Commonwealth’s Exhibit Nine was located inside the Bon’s Super Market by police the night of the shooting. Jeff Jenkins, grandson of Clyde Jenkins, and also an employee of the store, has identified this weapon as belonging to his grandfather. The weapon had not been fired.
J.A. at 57. And the revolver itself was presented into evidence as Commonwealth’s Exhibit Nine, without objection from Mr. El-Amin and without him asking any question concerning the location where the gun was found. J.A. at 57, 299. Therefore, the only question is whether, knowing that the gun was recovered at the scene of the crime, Barnes either actually knew, or reasonably could have obtained, the information as to precisely where the gun was found.
The record evidence plainly supports the state court’s conclusion6 that Barnes either knew or easily could have discovered the location of the victim’s gun through “a reasonable and diligent investigation.” Barnes’ co-defendant, James Corey, was tried less than two weeks before Barnes was tried. At Corey’s trial, Officer Banks, who retrieved the gun from the supermarket, testified that the gun was found underneath the victim’s body. J.A. at 577. Not insignificantly, this *977testimony was elicited by the same Commonwealth’s Attorney whom Barnes now alleges withheld the gun’s location. If petitioner’s counsel had attended Corey’s trial, read the trial transcript, or spoken with counsel for Barnes’ codefendant, he could have learned of the gun’s location. Alternatively, counsel could have obtained the allegedly “withheld” information by interviewing Officer Banks or any member of the rescue squad before trial, before sentencing, or before the first petition was filed. See Wilson, 901 F.2d at 381. The ease with which Mr. El-Amin could have obtained the information and the obviousness of its sources all but confirm that Barnes and his counsel made “a tactical decision” not to inquire about the location, as the district court concluded in its first memorandum opinion when addressing Barnes’ allegation that his counsel was ineffective for failing to investigate the location of the gun. See J.A. at 323.
The facts underlying Barnes’ exculpatory-evidence claim having been reasonably available to him before he filed his first habeas petition, the Supreme Court of Virginia’s finding that Barnes failed to show cause for his failure timely to raise his claim based upon this evidence was supported by the evidence of record.
B.
Even if Barnes could have shown cause, he could not have shown the requisite prejudice. To establish prejudice from an inability to present an exculpatory-evidence claim, a petitioner must demonstrate that the prosecution’s withholding of the exculpatory evidence “worked to his actual and substantial disadvantage, infecting his [sentencing] with error of constitutional dimensions.” United States v. Frady, 456 U.S. 152, 170, 102 S.Ct. 1584, 1596, 71 L.Ed.2d 816 (1982).
The district court concluded that the “withheld” information prejudiced Barnes’ sentencing because “the presence of a weapon on a murder victim, even if its presence is not known to the killer, is far from irrelevant.” J.A. at 690. In a somewhat remarkable argument, the court hypothesized that,
“Had the location of the gun been known to him, Mr. El-Amin, at the sentencing phase in this case, could have presented the Court with a scenario in which Mr. Barnes was confronted with an armed man rather than a helpless one. Under such a scenario, a fact finder could infer that in firing his own gun, Mr. Barnes was motivated by an understandable fear for his safety. Even when Mr. Jenkins was on the floor after Mr. Barnes’ first two shots, he was not completely incapacitated, as shown by his attempt to rise. Mr. Jenkins, although wounded, may have been within reach of a gun, and therefore may still have posed a significant danger to Mr. Barnes. In such a situation, the fact finder might well find that the nature of Mr. Barnes’ actions did not constitute an aggravated battery, and/or did not merit a sentence of death.
J.A. at 692. Thus, according to the district court, prejudice of constitutional magnitude exists in denying trial counsel the opportunity to argue at sentencing that Barnes was “motivated by an understandable fear for his safety,” from the “significant danger” of a seventy-three-year-old man who lay on the floor, shot twice,7 even though Barnes has never asserted — neither when he testified at his sentencing nor even today — that he saw a gun. Putting to one side the question of whether counsel would be permitted to argue that Barnes feared for his own life, given the complete absence of evidence or even suggestion that Barnes saw Jenkins’ gun, Virginia law renders a victim’s mere possession of a firearm irrelevant to whether an aggravated battery was committed. The state’s highest court has defined an aggravated battery as “a battery which, qualitatively and quantitatively, is more culpable than the minimum necessary to accomplish an act of murder.” M. Smith v. Commonwealth, 219 Va. 455, 248 S.E.2d 135, 149 (1978), cert. denied, 441 U.S. 967, 99 S.Ct. 2419, 60 L.Ed.2d 1074 (1979). In Barnes’ direct appeal, the Virginia Supreme Court further clarified that “a killing inflicted by multiple gunshot wounds may constitute an ‘aggravated battery’... where there is an appreciable lapse of time between *978the first shot and the last, and where death does not result instantaneously from the first.” Barnes, 360 S.E.2d at 203. Thus, the gravamen of aggravated battery is the number of wounds and the lapse of time between the first wound and the wound that immediately causes the death. The Supreme Court of Virginia so held even over the dissent’s protest that aggravated battery should include a notion that the victim was defenseless. Id. at 203-05. See also Boggs v. Bair, 892 F.2d 1193, 1197 (4th Cir.1989) (agreeing with the Virginia court “that the number or nature of the batteries inflicted upon the victim is a proper test as to whether the defendant’s conduct was outrageous or wantonly vile, horrible, or inhuman in that it involved an aggravated battery”), cert. denied, 495 U.S. 940, 110 S.Ct. 2193, 109 L.Ed.2d 521 (1990).8 Because the mere possession of a gun by the victim is irrelevant to whether an aggravated battery has been committed, the prosecution’s nondisclosure of the precise location of Jenkins’ gun as perhaps within Jenkins’ reach or possession could not have prejudiced Barnes’ effort to establish that his murder of Jenkins did not constitute an aggravated battery.
The Virginia Supreme Court’s decision in R. Smith v. Commonwealth, 239 Va. 243, 389 S.E.2d 871, cert. denied, 498 U.S. 881, 111 S.Ct. 221, 112 L.Ed.2d 177 (1990), confirms that the victim’s defenselessness vel non is immaterial to the aggravated-battery inquiry. In that case, the defendant fatally shot a police officer, after the armed officer approached him and, in the court’s words, a “gun battle” ensued. Id., 389 S.E.2d at 874-75. The Virginia court held that the jury’s finding of aggravated battery was “supported by the evidence of multiple wounds,” id. at 886, without even mentioning that the victim was not only armed, and the defendant undoubtedly knew he was armed, but, the victim actually shot the defendant at some point during the confrontation, id. at 875, 883, 885. Indeed, if the defendant’s account is believed, the victim shot first and he (the defendant) merely returned fire. Id. at 875, 881-82.9 The concurrence contends that “[a] review of the cases does not disclose a single instance where Virginia courts have upheld an aggravated battery finding when, on the facts as known to the court, the defendant inflicted the wound in response to the armed resistance of the victim.” Post at 982. Apparently, the concurrence has misread R. Smith.
In the same vein, the concurrence seriously misreads Chandler v. Commonwealth, 249 Va. 270, 455 S.E.2d 219 (1995), as clearly supporting the proposition that “[aggravated battery in Virginia for purposes of a finding of “idleness’ is premised on the existence of a victim who is not armed and not resisting.” Post at 982. The concurrence believes that this proposition is clearly established by the observation in that case that “[sentencing bodies in this Commonwealth have often imposed the death penalty where the victim was a store clerk, was unarmed, provided little or no resistance, and was killed at literally point blank range,” Chandler, 455 S.E.2d at 227. On its face, this language does not permit the inference drawn by the concurrence. When the passage is understood in context, it is even clearer that the passage in no way can be read as supporting the view of Virginia law taken by the concurrence. The court made this observation in the course of a proportionality review, during which it compares Chandler’s crime and sentence to comparable crimes and sentences of other defendants. The court of course noted that in similar contexts — where the victim was unarmed and non-resistant — that the death sentence had been imposed; those were facts of Chandler’s crime. Those circumstances, however, are no more necessary for imposing the death penalty than that the victim be a “store clerk,” a fact that was also *979recited by the court. If there were any remaining question as to the irrelevancy of Chandler to the case before us, it should be put to rest by the fact that Chandler does not in any way even discuss the “vileness” aggravating factor with which we are concerned, because Chandler was sentenced to death based on the future dangerousness predicate. Id. at 221, 227; see also supra note 1.
III.
In his related appeal, Barnes claims that he was denied effective assistance of counsel because his trial counsel failed to discover and present all available mitigating evidence. Specifically, Barnes contends that a proper investigation would have revealed that he was reared in a violence-ridden and abusive home, and that he was mentally impaired. At the federal evidentiary hearing on this claim, Barnes presented examples of the evidence he contends El-Amin should have elicited, including testimony from his mother, grandmother, and half-brother, and from three experts, a psychiatrist, a neuropsychologist, and a psychiatric social worker.10 The district court correctly concluded that Barnes had failed to satisfy the first requirement of Strickland v. Washington, 466 U.S. 668, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984), that “in light of all the circumstances, the identified acts or omissions [of counsel be] outside the wide range of professionally competent assistance,” id. at 690, 104 S.Ct. at 2066. J.A. at 676-84.11
The Supreme Court has provided guidance for determining whether an attorney’s investigation into matters that might aid his client constitutes deficient representation:
[Strategic choices made after less than complete investigation are reasonable precisely to the extent that reasonable professional judgments support the limitations on investigation. In other words, counsel has a duty to make reasonable investigations or to make a reasonable decision that makes particular investigations unnecessary. In any ineffectiveness case, a particular decision not to investigate must be directly assessed for reasonableness in all the circumstances, applying a heavy measure of deference to counsel’s judgments.
The reasonableness of counsel’s actions may be determined or substantially influenced by the defendant’s own statements or actions. Counsel’s actions are usually based, quite properly, on informed strategic choices made by the defendant and on information supplied by the defendant. In particular, what investigation decisions are reasonable depends critically upon such information. ... [W]hen a defendant has given counsel reason to believe that pursuing certain investigations would be fruitless or even harmful, counsel’s failure to pursue those investigations may not later be challenged as unreasonable.
Strickland, 466 U.S. at 690-91, 104 S.Ct. at 2066. In particular as it relates to Barnes’ claim, trial counsel is not obligated to seek a psychological examination and may rely on the truthfulness of his client and those whom *980he interviews in deciding how to pursue his investigation. See Clanton v. Bair, 826 F.2d 1354, 1358 (4th Cir.1987), cert. denied, 484 U.S. 1036, 108 S.Ct. 762, 98 L.Ed.2d 779 (1988).
Applying this standard, it is evident, as the district court concluded, that El-Amin’s decision to limit his investigation and to not present certain mitigating evidence was reasonable, based on his assessment of the law and his interviews with Barnes and his family. El-Amin testified that he reviewed the relevant Virginia law and concluded that his primary task at the sentencing hearing was to prevent a finding of “future dangerousness,” since he believed that it was less likely that the court would find that the circumstances of these murders were vile or constituted an aggravated battery. J.A. at 547-49. This tactical approach required that El-Amin portray Barnes as a sane or nonviolent individual. In preparing for this presentation, El-Amin interviewed Barnes on several occasions and questioned his mother and grandmother repeatedly, all of whom spoke positively about Barnes’ family background, never suggesting in any way that his mental health was in doubt. J.A at 549-50, 555. At the district court hearing, El-Amin recounted that,
Herman spoke well of his background. I learned from him and his mother and his grandmother that he had what I understood at the time to be a supportive family; that he was very, very dependent, almost to a fault. He had extreme love and a protective relationship with his mother and grandmother.... So there was never any indication of any ill will that was directed toward his background in terms of growing up other than just being influenced by the streets.
J.A. at 555. Barnes’ probation officer from Philadelphia confirmed El-Amin’s belief that the family situation was strong, and nothing in the presentence report, arrest records, or probation records refuted this impression. J.A. at 560-61, 566-67. Simply, El-Amin did not seek evidence of childhood abuse or mental impairment because there was “no indication” that such evidence existed and because such evidence would not have been “germane to [his] defense.” J.A. at 556. Indeed, he believed that evidence of pathology would have been counterproductive to his strategy. As the district court recognized, El-Amin “made a tactical decision not to [pursue a psychiatric or similar evaluation],” J.A. at 683-84, because it would have been “cross-purpose evidence” that might have led the sentencing authority to conclude that Barnes posed a continuing threat to society, J.A. at 554. Barnes, thus, is the paradigm of “a defendant [who] has given counsel reason to believe that pursuing certain investigations would be fruitless or even harmful.” Strickland, 466 U.S. at 691, 104 S.Ct. at 2066. See Burger v. Kemp, 483 U.S. 776, 793-95, 107 S.Ct. 3114, 3125-26, 97 L.Ed.2d 638 (1987).
El-Amin decided not to present the good character evidence that he learned ft’om Barnes’ mother and grandmother because he believed that if vileness were found, traditional character evidence, under the circumstances and given its source, would not lead the judge to impose life imprisonment. J.A. at 559. This was likewise a reasonable tactical choice, see Fitzgerald v. Thompson, 943 F.2d 463, 470 (4th Cir.1991), cert. denied, 502 U.S. 1112, 112 S.Ct. 1219, 117 L.Ed.2d 456 (1992); Turner v. Williams, 35 F.3d 872, 900-03 (4th Cir.1994), cert. denied, — U.S. -, 115 S.Ct. 1359, 131 L.Ed.2d 216, 1995 WL 23496 (U.S., Mar. 20, 1995). Barnes has not overcome the presumption that his counsel’s decision constituted sound trial strategy. See Strickland, 466 U.S. at 699-700, 104 S.Ct. at 2070-71; Burger, 483 U.S. at 788-96, 107 S.Ct. at 3122-27; Bunch v. Thompson, 949 F.2d 1354, 1363-65 (4th Cir.1991), cert. denied, — U.S. -, 112 S.Ct. 3056, 120 L.Ed.2d 922 (1992).
Of course, even if Barnes were able to show that El-Amin should have presented the evidence of abuse and dysfunction, it is unlikely that he could have satisfied Strickland’s second requirement of a “reasonable probability” that the outcome would have been different but for El-Amin’s failure to develop this case in mitigation. As the Supreme Court observed in Penry v. Lynaugh, 492 U.S. 302, 109 S.Ct. 2934, 106 L.Ed.2d 256 (1989), evidence of a defendant’s mental impairment “may diminish his blameworthiness for his crime even as it indicates that there is *981a probability that he will be dangerous in the future.” Id. at 324, 109 S.Ct. at 2949. El-Amin testified, and the district court agreed, that producing evidence of Barnes’ mental condition increased the likelihood that the court would find that Barnes posed a future threat. See J.A. at 554 (El-Amin testifying that he was trying to portray Barnes “as a non-violent individual_ I don’t want to create a record of violence on his part. Because that would have thrown me into the future dangerousness issue and ... I was trying to minimize that evidence.”). Thus, the sentencing authority could well have found in the mitigating evidence of mental illness or history of abuse, sufficient evidence to support a finding of future dangerousness.
CONCLUSION
The judgment of the district court granting the petitioner’s writ of habeas corpus is reversed and the case is remanded with instructions to reinstate the death sentence. That portion of the district court’s order finding that the petitioner received effective assistance of counsel is affirmed.
REVERSED IN PART AND AFFIRMED IN PART.
. Under Virginia's death penalty scheme, a defendant may be sentenced to death if the sentencing authority finds either one of two aggravating factors: (1) "that there is a probability that the defendant would commit criminal acts of violence that would constitute a continuing serious threat to society” (the "future dangerousness" predicate), or (2) “that his conduct in committing the offense ... was outrageously and wantonly vile, horrible or inhuman in that it involved torture, depravity of mind or aggravated batteiy to the victim" (the "vileness" predicate). Va. Code Ann. § 19.2-264.2; see Turner v. Williams, 35 F.3d 872, 877 (4th Cir.1994), cert. denied, - U.S. -, 115 S.Ct. 1359, 131 L.Ed.2d 216 (1995); Boggs v. Bair, 892 F.2d 1193, 1196-97 (4th Cir.1989), cert. denied, 495 U.S. 940, 110 S.Ct. 2193, 109 L.Ed.2d 521 (1990).
. The concurrence would resolve Barnes’ appeal by proceeding directly to the merits of his Bagley claim, bypassing altogether the federal cause and prejudice inquiry. This approach, of course, is not permitted to us under Supreme Court precedent. See Coleman, 501 U.S. at 750, 111 S.Ct. at 2565 ("In all cases in which a state prisoner has defaulted his federal claims in state court pursuant to an independent and adequate state procedural rule, federal habeas review is barred unless the prisoner can demonstrate cause for the default and actual prejudice as a result of the alleged violation of federal law...." (emphasis added)).
The concurrence also maintains that it would "find[] that Barnes ha[d] not defaulted his Bagley claim in state court.” Post at 985; id. at 985-86. This course is likewise foreclosed under law. A basic tenet of federal habeas review is that a federal court does not have license to question a state court's finding of procedural default, if based upon an adequate and independent state ground. Harris v. Reed, 489 U.S. 255, 262, 109 S.Ct. 1038, 1042, 103 L.Ed.2d 308 (1989); Ashe v. Styles, 39 F.3d 80, 85-86 (4th Cir.1994) (Murnaghan, J., joining). The federal court may only inquire into whether cause and prejudice exist to excuse that default, not into whether the state court properly applied its own law. Id. The concurrence quite obviously has confused an inquiry for cause with an inquiry into the default determination.
Of course, if one does not appreciate that the cause and prejudice inquiiy is mandated and that the state procedural default finding is binding on a federal court, then one will indeed believe, as the concurrence does, that within the opinion for the court there are "many statements of dicta and alternative holdings.” Post at 988.
. Section 2254(d) applies only to "determination[s] after a hearing on the merits of a factual issue.” However, as the Supreme Court observed in Sumner v. Mata, 449 U.S. 539, 101 S.Ct. 764, 66 L.Ed.2d 722 (1981):
[Section 2254(d) does not] specify any procedural requirements that must be satisfied for there to be a “hearing on the merits of a factual issue,” other than that the habeas applicant and the State or its agent be parties to the state proceeding and that the state-court determination be evidenced by "a written finding, written opinion, or other reliable and adequate written indicia.”
Id. at 546-47, 101 S.Ct. at 769.
. While the concurrence, in discussing the merits of the Bagley claim, acknowledges that the defendant is obliged to exercise reasonable diligence, it believes that the duty is relinquished once the defendant asks the prosecutor for exculpatory evidence. Post at 984. This, too, see supra note 2, reflects a misunderstanding of the law, and in particular the Brady doctrine. Brady requires that the government disclose only evidence that is not available to the defense from other sources, either directly or through diligent investigation. Stockton, 41 F.3d at 927; Wilson, 901 F.2d at 380 ("government has no Brady burden when facts are available to a diligent defense attorney” (parenthetical to Lugo v. Munoz, 682 F.2d 7, 9-10 (1st Cir.1982))). Nondisclosure, therefore, does not denote that no exculpatory evidence exists, but that the government possesses no exculpatory evidence that would be unavailable to a reasonably diligent defendant. Accordingly, it is unexceptional when this court finds that Brady affords a defendant no relief if he fails to pursue exculpatory evidence, notwithstanding his specific request for such evidence. See, e.g., Stockton, 41 F.3d at 923, 927. Of course, even where the government impermissi-bly withholds exculpatory evidence, a Brady violation does not arise unless the undisclosed evidence was material. United States v. Bagley, 473 U.S. 667, 669, 105 S.Ct. 3375, 3376, 87 L.Ed.2d 481 (1985); Brady v. Maryland, 373 U.S. 83, 87, 83 S.Ct. 1194, 1196, 10 L.Ed.2d 215 (1963).
. The examination went as follows:
Q (by Mr. El-Amin): Detective Browning, I have some questions directed to some evidence that was obtained. Two thirty-eight caliber revolvers were recovered and submitted to the lab is that correct?
A (by Detective Browning): Yes.
Q: Where did you get them?
A: One [Jenkins' gun] was recovered at the scene, shortly after the incident occurred. The other [the murder weapon] was recovered on Saturday after the incident.
Q: Where was the one recovered Saturday?
H * • * * * *
Q: All right, and the thirty-eight caliber that was found at or near the scene, had that been fired?
A: No.
J.A. at 299-300.
. The concurrence asserts that "the state court never [made] such a finding.” Post at 984. This assertion, tellingly made in its discussion of the merits and referring, of course, to our discussion of cause, reveals a failure on the part of the concurrence to appreciate the procedural default rule relied upon by the Virginia court and a refusal to abide by our court’s own precedents. See discussion supra at 974-75. It bears repeating that a default determination under section 8.01 — 654(B)(2), which provides that "[n]o writ shall be granted on the basis of any allegation the facts of which petitioner had knowledge at the time of filing any previous petition,” reflects a finding that indeed the petitioner either knew or had available all of the facts on which the current petition was based. See Waye, 884 F.2d at 766; Stockton, 41 F.3d at 925. While this finding is often implicit (as here), it is a finding nonetheless, and must be accorded presumptive validity. Id. at 924—25; see also post at 985-86.
Even if the concurrence was correct in its assertion that a state court finding under § 8.01-654(B)(2) does not entail a finding of reasonable availability of the facts underlying the current petition, post at 984-85 n. 5, and even if we were not bound by our precedents to the contrary, the point is of no significance. If the state court found only that Barnes knew at the time of his previous petition that the government had not produced information as to the gun's location, this factual finding is likewise amply supported by the record — if by nothing else, by the fact that Barnes knew the gun was recovered at the scene of the crime and did not inquire into the gun’s location. Therefore, the claim would still be barred.
We simply have no idea what the concurrence means when it says that our reference in Stockton to the petitioner’s actual or constructive knowledge "does not relate to a Virginia state court finding under Virginia Code § 8.01-654(B)(2).” Post at 984-85 n. 5. The entire issue in Stockton was whether the petitioner had shown cause to excuse his procedural default under § 8.01-654(B)(2). See 41 F.3d at 924-25. The opinion could not be any clearer.
. The first shot penetrated Jenkins' chest, collapsing the left lung and perforating the aorta, while the second shot entered the abdomen and lacerated the liver. Barnes, 360 S.E.2d at 199. With these wounds, we find hollow El-Amin's contention on Barnes’ behalf that after the two shots, Jenkins "was still combative and capable of joining the combat.” J.A. at 548.
. Notably as it bears on the question of prejudice, the Commonwealth never argued at sentencing that Mr. Jenkins was defenseless when he was shot.
. The concurrence suggests that we "inexplicably rel[y] on defendant Smith’s version of events.” Post at 982 n. 3. We do not. The Virginia court presented the facts, as undisputed, that the victim carried a nine-millimeter revolver, 389 S.E.2d at 875, and that the defendant was shot by that revolver, id., at 874—75, 874 n. 3. The Virginia court concluded further that the evidence entitled the jury to believe, as it did, that the defendant knew the victim was an armed police officer. Id. at 878, 880-81. Moreover, the testimony of Officer James K. Ryan suggested, based upon the distinctive sounds of the gun fire, that the defendant continued shooting after the officer-victim shot his handgun. Id. at 874, 874 n. 3.
. The Commonwealth objected to the admission of some of this evidence, arguing that under Keeney v. Tamayo-Reyes, 504 U.S. 1, 112 S.Ct. 1715, 118 L.Ed.2d 318 (1992), a federal court is limited to the record presented to the state court, and since Barnes had not presented the state court with any psychiatric or neurological evidence, the reports of the psychiatrist and the neuropsychologist should not be considered by the district court. J.A. at 340-41. The district court did not rule directly on the respondent’s objection, but instead stated that it would "hear the evidence” but not necessarily “consider” it. J.A. at 343. For purposes of this decision only, we assume that admission of this evidence was not error.
. Under Strickland, a defendant, or in this case a petitioner, asserting a claim of ineffective assistance of counsel must show both that his attorney’s performance was deficient and that it prejudiced the defense. 466 U.S. at 687, 104 S.Ct. at 2064. To show deficiency, the petitioner must demonstrate that his attorney’s representation “fell below an objective standard of reasonableness." Id. at 688, 104 S.Ct. at 2064. In order to show prejudice where a petitioner is challenging his death sentence, he must establish a reasonable probability that, absent counsel's errors, the sentencer. — including an appellate court, to the extent it independently reweighs the evidence— would have concluded that the balance of aggravating and mitigating circumstances did not warrant death. See id. at 695, 104 S.Ct. at 2068.