Petitioner-appellant Phillip DeWitt Smith appeals from the district court’s denial of his petition for habeas relief, see 28 U.S.C. § 2254, from his Oklahoma first degree murder conviction and death sentence. On appeal, he raises seven grounds for relief: 1) prosecutorial misconduct; 2) an evidentiary harpoon resulting from a witness volunteering that petitioner had kidnaped his daughter; 3) the lack of a cautionary instruction regarding an informant’s testimony; 4) ineffective representation at sentencing; 5) the trial court’s failure to instruct the jury on lesser included offenses; 6) double counting of aggravating circumstances; and 7) the unconstitutionality of the continuing threat aggravating circumstance. We affirm the denial of habeas relief.
I. FACTS
Petitioner was convicted of bludgeoning to death an acquaintance, Matthew Taylor. Taylor was murdered in his apartment during the early morning hours of November 4, 1983. He had been beaten with a blunt object, most likely a hammer. When he was found the following afternoon, the victim’s front pants pockets had been turned inside out.
During a party at the victim’s home the previous evening, petitioner had agreed with the victim to share some marijuana. The victim had taken a twenty dollar bill from his front pants pocket, noting it was the smallest bill he had, and gave it to petitioner to go purchase the marijuana. Petitioner never returned to the party.
*458 At approximately midnight, petitioner borrowed a hammer from another acquaintance, indicating he was helping a friend fix a car. Petitioner then had Victor Hickman drive him to the victim’s apartment. Petitioner told Hickman that he was trying to collect money people owed him because he wanted to purchase a bus ticket to California. According to Hickman, petitioner went into the victim’s apartment, while Hickman waited in the car. When petitioner returned, he had a small stain of what appeared to be blood on his shirt.
In addition to this evidence, petitioner’s cellmate, Billy Joe Dickson, 1 testified that petitioner admitted to him that petitioner had killed the victim. The jury convicted petitioner of first degree murder.
During sentencing, the jury found the existence of three aggravating circumstances: 1) petitioner had been convicted of a prior violent felony; 2) the murder was especially heinous, atrocious or cruel; and 3) petitioner was a continuing threat to society. After weighing those aggravating circumstances with petitioner’s mitigating evidence, the jury sentenced petitioner to death.
The Oklahoma Court of Criminal Appeals affirmed his conviction and sentence on direct appeal.
See Smith v. State,
Petitioner filed his federal habeas petition February 21, 1995, prior to the enactment of the Antiterrorism and Effective Death Penalty Act (AEDPA). That Act, therefore, does not apply in this case.
See Lindh v. Murphy,
II. PROSECUTORIAL MISCONDUCT
Petitioner alleges the prosecutor knowingly misled the jury into believing Dickson was not testifying pursuant to a deal with prosecutors, when in fact he was.
See Gray v. Netherlands
At the time he testified against petitioner, Dickson had been charged, in an unrelated case, with burglary, after former conviction of a felony. If convicted, he faced a possible twenty year prison sentence. In his testimony at petitioner’s trial, Dickson asserted that he had no deal with prosecutors in exchange for his testimony, but that he was testifying against petitioner because petitioner had threatened Dickson while the two were jailed together. A few days after petitioner’s trial, the State dropped the after former conviction of a felony portion of Dickson’s pending burglary charge. He pled guilty and was released based on time already served.
Petitioner, however, asserts no credible evidence that prosecutors ever offered Dickson leniency in exchange for his testimony against petitioner. “The mere fact that ... [a] witness[ ] w[as] subsequently allowed to plead on favorable terms is not evidence that ... [a] plea agreement ]
*459
w[as] secretly reached prior to the witnesses] testimony....”
United States v. Molina,
At his state post-conviction hearing, two inmates did testify that Dickson admitted to them that he had lied at petitioner’s trial, about both not having a deal with prosecutors in exchange for his testimony and. petitioner’s jailhouse confession. Petitioner’s post-conviction counsel and his investigator also asserted that Dickson had told them that his trial testimony was false and that he had testified against petitioner pursuant to an understanding with the district attorney’s office.
Nonetheless, Dickson testified at that same evidentiary hearing, affirming the truth of his trial testimony and denying any agreement with the prosecution in exchange for his testimony. The district attorney also testified, acknowledging that his office had a policy of offering lenient treatment in exchange for testimony, but asserting that he had never spoken with Dickson about his testimony prior to petitioner’s trial. 2
The Oklahoma Court of Criminal Appeals implicitly found Dickson’s testimony credible.
See Smith,
Petitioner, nevertheless, argues this court should not presume that the state court’s credibility determination is correct in this case because he had no opportunity for discovery in the state post-conviction proceedings. See 28 U.S.C. § 2254(d) (pre-AEDPA). Review of the record, however, establishes that the state trial court did permit discovery in the post-conviction proceeding. Petitioner received all requested documents that existed, in addition to obtaining the state trial court’s in camera inspection of the prosecutor’s file to determine if there was any other relevant material that had not been produced. We, therefore, presume the state appellate court’s credibility determination was correct.
Petitioner asserts that the district court erred in denying him further discovery on this issue in federal court. A federal habeas petitioner, however, will be entitled to discovery only “if, and to the extent that, the [district court] judge in the exercise of his discretion and for good cause shown grants leave to do so, but not otherwise.” Rule 6(a), Rules Governing Section 2254 Cases;
see, e.g., Bracy v. Gramley,
Lastly, petitioner challenges as false Dickson’s testimony at sentencing that petitioner possessed a shank while in
*460
jail awaiting trial. In order to recover on this claim, petitioner had to establish that the prosecutor'
knowingly
presented false testimony.
See, e.g., Medina v. Barnes,
III. EVIDENTIARY HARPOON
Within his prosecutorial misconduct argument, petitioner also challenges the evi-dentiary “harpoon” resulting when Dickson, at trial, volunteered that petitioner had been charged with kidnaping his daughter. The State had previously agreed not to present evidence regarding this incident, in response to petitioner’s motion in limine. At the close of the first stage, the trial court did instruct the jury to limit its consideration of other crimes evidence to motive. Petitioner asserts he suffered prejudice from this evidence at both the guilt and sentencing stages of the proceeding.
Petitioner will be entitled to relief on this claim only if he can establish that the admission of this testimony rendered the trial fundamentally unfair.
See, e.g., Scrivner v. Tansy,
IV. CAUTIONARY INSTRUCTION
Petitioner asserts the trial court erred in failing, sua sponte, to instruct the jurors to view Dickson’s testimony, as that of an informer, with caution and distrust. Respondents contend this argument is procedurally barred. On direct appeal, the Oklahoma Court of Criminal Appeals reviewed the merits of this claim under a fundamental error analysis, holding that such an instruction was not necessary under state law.
See Smith,
Because petitioner has failed to assert a recognized federal constitutional right to a cautionary jury instruction regarding an informant’s testimony, he will be entitled to habeas relief on this claim only if the trial court’s refusal to give the instruction resulted in a fundamentally unfair trial.
Cf. Foster,
V.INEFFECTIVE ASSISTANCE OF COUNSEL
Petitioner asserts four ways in which his trial attorney was ineffective during sentencing. Respondents do not argue to this court that these claims are procedurally barred.
See Hooks,
Petitioner will not be entitled to habeas relief on these claims unless he can establish both that his attorney’s performance was deficient and that he was thereby prejudiced.
See Strickland v. Wash
*461
ington,
A. Conceding Appropriateness of Death Penalty
Petitioner argues defense counsel, during his first-stage closing argument, conceded that this crime was “cruel,” thus admitting the “especially heinous, atrocious or cruel” aggravating circumstance, and that the crime warranted the death penalty. Representative of the remarks petitioner challenges, defense counsel told jurors not to “kid yourselves, ladies and gentlemen. If you find that [petitioner] ... brutally murdered [the victim] ..., the penalty you’re going to impose is going to be the very severe one.” Trial tr. at 767. Defense counsel also suggested the murderer was an “animal” and he emphasized the gruesomeness of the crime scene. The uncontroverted evidence, however, including a number of gruesome photographs of the crime scene and the victim’s body, established that the victim was brutally murdered. Defense counsel could not have argued otherwise credibly.
From the tenor of his entire argument, defense counsel made these remarks for two reasons supporting his contention that petitioner was innocent. First, counsel argued that, if petitioner had wanted to rob the victim, he would not have needed to kill him, in light of the victim’s intoxicated state at the time of death. Further, even if the robber thought murdering the victim was necessary, there was no need to have committed such a brutal murder. This supported defense counsel’s argument to the jury that robbery was not a sufficient explanation for such a brutal slaying and that there must have been something more going on than the purported robbery— perhaps the murderer was someone other than petitioner who had a score to settle with the victim or to whom the victim owed drug money.
Secondly, defense counsel emphasized the bloodiness of the crime scene, both in his cross-examination and closing argument, to support his contention that the murderer would have had to have had blood all over him after the killing. Only Hickman testified that petitioner had what appeared to be blood on him after returning from the victim’s apartment, and that was only a single spot one to two inches in diameter.
Petitioner argues both that trial counsel’s argument was per se ineffective and, alternatively, was deficient performance prejudicial to petitioner under
Strickland.
Considering the whole of his argument, however, counsel did not “abandon[] his duty of loyalty to his client and effectively join[] the state in an effort to attain a conviction or death sentence” such that counsel’s performance could be deemed per se ineffective.
Davis v. Executive Dir. of Dep’t of Corrections,
*462
Further, counsel’s performance was not deficient under
Strickland.
These remarks were reasonable trial strategy in light of the circumstantial nature of the evidence against petitioner.
See Moore v. Gibson,
Petitioner also challenges defense counsel’s second-stage closing argument, asserting counsel continued to argue in this same vein, targeting any residual doubt the jurors might have had concerning petitioner’s guilt. But “residual doubt has been recognized as an extremely effective argument for defendants in capital cases.”
Lockhart v. McCree,
B. Failure to Prepare Petitioner to Testify at Sentencing
Petitioner claims that his attorney failed to prepare petitioner to testify at sentencing. Petitioner told jurors at sentencing that he had not committed the crime and asked them not to sentence him to death so that he would have an opportunity to prove his innocence.
In the state post-conviction proceedings, petitioner testified that counsel did not ask him if he wanted to testify until immediately prior to sentencing and did not advise him of the questions the attorney intended to ask, but rather told petitioner just to tell the jurors what he wanted to tell them. On the other hand, defense counsel testified at the post-conviction hearing that petitioner did not decide to testify at sentencing until the last minute and that counsel did discuss petitioner’s testimony with him, but would not tell him what to say. The state court did not make any factual findings or credibility determinations concerning this inconsistent testimony.
Nonetheless, even if we assume counsel’s performance was deficient, petitioner has failed to establish any resulting prejudice.
See Cooks,
Petitioner also argues that trial counsel should have used petitioner’s testimony to explore the facts of his prior rape conviction. At the state post-conviction hearing, however, trial counsel testified that, as a matter of strategy, he did not go into the details of the prior conviction in order to prevent the prosecution from presenting the rebuttal testimony of the rape victim. Petitioner has failed to overcome the presumption that this was reasonable strategy under the circumstances.
See Strickland,
C. Failure to Request Mental Health Expert
Petitioner argues that trial counsel was ineffective for failing to request the assistance of a mental health expert, both to rebut the State’s allegation of petitioner’s future dangerousness and to assist in presenting mitigating evidence. Because the State presented evidence of petitioner’s future dangerousness, petitioner would have been entitled to appointed psychiatric assistance for sentencing if he could have established the likelihood that his mental condition was a significant mitigating factor.
See Rogers v. Gibson,
*463
At the post-conviction hearing, trial counsel asserted that there was nothing that led him to believe petitioner was not competent. Further, the trial record does not contain any suggestion that petitioner’s mental condition could have been a significant mitigating factor. Counsel’s failure to request a psychiatric expert, therefore, was not deficient.
See, e.g., Wilson v. Henry,
Even if counsel’s performance was deficient, however, petitioner has not shown that this deficiency prejudiced him. A 1995 post-conviction psychological evaluation indicated only that petitioner possesses low average intelligence and suffers from organic brain damage which impairs his judgment and causes him to act impulsively. While this evaluation would have been proper mitigating evidence, this court has, “on numerous occasions determined that ... evidence of low I.Q. and/or organic brain damage” “does not outweigh evidence supporting ... multiple aggravating circumstances,”
Foster,
D. Failure to Investigate Mitigating Evidence Adequately
Petitioner contends that defense counsel was ineffective for failing to investigate other possible mitigating evidence. Counsel has a duty to conduct reasonable investigation for mitigating evidence or to make a reasonable decision that particular investigation is unnecessary.
See, e.g., Stouffer v. Reynolds,
Even assuming counsel’s investigation and preparation of mitigating evidence was deficient, petitioner is unable to show prejudice. Petitioner submits the affidavits and deposition testimony of a number of people indicating that, had they been asked, they would have testified in petitioner’s behalf at sentencing. Those witnesses include a number of family members, the mothers of petitioner’s two children, friends, his childhood pastor, a coach and a former boss. These witnesses assert they could have offered testimony concerning petitioner’s close family; the effect of his mother’s death on him; his love and care for his children and his family; his reliability and good attitude at work; his easy going, likable personality; his school and athletic activities; his church attendance as a youth; his politeness and respect for others; and his history of nonviolence. Petitioner also asserts that the testimony of the mother of his child living in California could have ameliorated the earlier evidence concerning his kidnaping his daughter.
Petitioner, however, is unable to show that this mitigating evidence would have resulted in the jury sentencing him to life in prison, in light of the brutal and senseless nature of this crime and the strength of the State’s evidence supporting the three aggravating circumstances, including evidence of a prior rape conviction, his threatening a cellmate, and his possession of a weapon in jail.
See Boyd,
VI. LESSER INCLUDED OFFENSE INSTRUCTION
Petitioner argues that the trial court erred in not instructing the jury on second degree felony murder or first degree manslaughter, in violation of
Beck v. Alabama,
Because petitioner did not request the trial court instruct the jury on any lesser included offense, however, he cannot prevail on this claim.
See Hooks,
[w]here a state has in place a system by which a criminal defendant has a right to an instruction on lesser included offenses supported by the evidence, as Oklahoma does, and the defendant chooses not to request an instruction thereby failing to alert the court to the propriety of such an instruction Beck does not require reversal on federal ha-beas.
Id. at 1235.
VII. DUPLICATIVE AGGRAVATING CIRCUMSTANCES
Petitioner argues that all three aggravating circumstances found by the jury that the murder was especially heinous, atrocious or cruel, petitioner had a prior violent felony conviction, and he presented a continuing threat to society unconstitutionally overlap. “ ‘[D]ouble counting of aggravating factors, especially under a weighing scheme, [such as Oklahoma’s capital procedure,] has a tendency to skew the weighing process and creates the risk that the death sentence will be imposed arbitrarily and thus, unconstitutionally.’ ”
Id.
at 1239 (quoting
United States v. McCullah,
VIII. CONTINUING THREAT AGGRAVATING CIRCUMSTANCE
Petitioner argues that Oklahoma’s “continuing threat” aggravating circumstance is unconstitutionally vague and overbroad because it fails to narrow the class of murderers eligible for a death sentence. This court has previously rejected this argument.
See, e.g., Castro v. Ward,
IX. CONCLUSION
Having carefully considered the record and the parties arguments asserted on appeal, we AFFIRM the district court’s denial of § 2254 relief. The court also denies *465 petitioner’s “Motion to Remand,” filed with this court November 16,1999.
Notes
. Although the trial transcript refers to this witness as Dickson, elsewhere in the record he is referred to as Dixon.
. We reject petitioner’s argument that the prosecutor thus deceived jurors when he told them that his office did not have such a policy. The prosecutor’s remarks, during closing argument, were focused solely on the lack of any deal with Dickson, rather than the existence of a broader policy in general.