KRAVITCH, Circuit Judge:
Charles Michael Kight appeals from the district court’s denial of his petition for a writ of habeas corpus. We hold that Kight is not entitled to relief as to his conviction or his sentence. Accordingly, we AFFIRM.
I.
On December 7, 1982, Florida police arrested Charles Michael Kight and Gary Hut-to in connection with the robbery of a black taxicab driver, Herman McGoogin. Kight and Hutto were apprehended separately, each near the scene of the robbery; MeGoo-gin made on-sight identifications of the two men. Kight possessed a knife at the time of his arrest.
On December 14,1982, the body of another black cab driver, Lawrence Butler, was discovered. Butler had been stabbed fifty-one times. On December 17, 1982, Detective Weeks removed Kight from his cell in order to retrieve the clothes that Kight had been wearing on the night he was arrested for the McGoogin robbery.
When Weeks and Kight reached the property room, Kight remarked, “I’m not afraid of the chair.” Weeks asked Kight, “what chair are you talking about,” and Kight responded, “the electric chair ... because Hutto cut [the cab driver’s] throat, and he got his watch on.” At this point, Weeks stopped Kight in order to read him his
Miranda
rights. After Kight orally waived his rights, Weeks contacted the detective in charge of the Butler murder investigation. Kight signed a written waiver of his constitutional rights to remain silent and to have an attorney present and gave a transcribed statement. Kight admitted being present during the murder, but told police that Hutto had committed the act and that he had known nothing about a plan to rob or murder prior to entering Butler’s cab.
Kight was charged with first-degree murder.
During his trial, the prosecution presented the testimony of a forensic expert, who indicated that tests performed on the clothes that Kight was wearing on the night of his arrest contained blood stains consistent with Butler’s blood. Additionally, McGoogin testified that when he was robbed by Kight and Hutto, it was Kight who had held the knife to his throat and used racial epithets. Further, four jailhouse inmates testified that Kight had told them that he had stabbed a cab driver and was going to “put the [murder charge] on” Hutto.
At trial, Hutto testified that on the night of Butler’s murder, he had passed out and woke up in a cab.
Kight was outside of the cab, stabbing the driver who was wearing only his underpants. Hutto further testified that during the McGoogin robbery he had tried to save McGoogin by pulling the knife which
Kight was holding away from McGoogin’s throat.
The defense argued that Kight was present for the murder but that Hutto had committed it. The jury was read Kight’s confession, in which he admitted being present, but stated that Hutto had committed the crime, and that he had not known about the robbery or murder in advance. The defense introduced forensic evidence demonstrating that blood on Hutto’s pants matched Butler’s blood. Additionally, one witness testified that Hutto had told her that he had stabbed someone and taken a black jacket from the victim. A fellow inmate testified that Hutto had confessed to him that he had killed a cab driver and that Kight did not know anything about it.
The jury found Kight guilty. At the sentencing phase of his trial, Kight’s attorney introduced mitigating evidence consisting of the testimony of Kight’s mother and sister that Kight had a poor childhood, was physically abused by his father and stepfather, spent time in a foster home, could not read or write, and was in special education classes in school. Kight’s sister testified that Kight had once apprehended a robber and received a medal for this deed. Additionally, Kight’s school records, indicating that he had never completed the ninth grade, were introduced. Finally, the defense called Dr. Krop, a psychologist, who testified that Kight was mentally retarded and had an I.Q. of 69, which placed him in the lowest two percent of the population. Krop also testified that in his opinion, Kight “would be very passive, he would be very dependent, he would be very easily influenced, he could be very easily manipulated.” He further indicated that Kight had a drug and alcohol problem.
The jury was instructed on three aggravating circumstances:
(a) A capital felony was committed while the defendant was engaged or was an accomplice in the commission of or at [sic] attempt to commit, or flight after committing, or attempting to commit a robbery;
(b) the capital felony was committed for the purpose of avoiding or preventing a lawful arrest or effecting an escape from custody; [and] (c) the capital felony was especially heinous, atrocious or cruel.
The jury was not given a narrowing instruction for the “heinous, atrocious or cruel” aggravating circumstance.
The jury was also instructed on four statutory mitigating circumstances
and was told to consider “any other aspect of the defendant’s character or record or any other evidence of the offense” for mitigation purposes. A majority of the jury recommended that the court impose the death penalty upon Kight.
The court found two aggravating circumstances: that the murder was committed during the commission of a robbery and that the offense was committed in a heinous, atrocious and cruel manner;
and found no statutory mitigating factors. The court found two nonstatutory mitigating factors: that Hutto received life imprisonment and that Kight had once “pursued and tackled a robber and held him until the police arrived.” After weighing the mitigating and aggravating factors, the court concluded that the aggravating factors outweighed the mitigating factors and sentenced Kight to death.
Kight’s conviction and sentence were affirmed on direct appeal.
See Kight v. State,
512 So.2d 922 (Fla.1987),
cert. denied,
485 U.S. 929, 108 S.Ct. 1100, 99 L.Ed.2d 262 (1988). Eight filed a Rule 3.850 motion for posteonviction relief, which was denied following an evidentiary hearing on Kight’s
Brady
claim.
See
Fla.R.Crim.P. 3.850. Eight appealed from this denial and, at the same time, filed a petition for a writ of habeas corpus with the Florida Supreme Court. That Court denied Eight’s petition for a writ of habeas corpus and affirmed the trial court’s denial of his Rule 3.850 motion.
See Kight v. Dugger,
574 So.2d 1066 (Fla.1990). Eight then filed a second petition for a writ of habeas corpus in the Florida Supreme Court, asserting that his death sentence was unconstitutional because the trial court did not give the jury a narrowing instruction for the “heinous, atrocious or cruel” aggravating circumstance. The Court summarily denied relief without issuing an opinion.
See Kight v. Singletary,
618 So.2d 1368 (Fla.1993).
Eight filed a petition for a writ of habeas corpus in the Middle District of Florida pursuant to 28 U.S.C. § 2254, asserting eighteen claims.
The district court denied his petition without holding an evidentiary hearing; the court held some claims to be procedurally barred
and denied the remaining claims on the merits. On appeal, Eight abandons all but eight of his claims,
so we address only those claims that Eight has presented to this court.
II.
Absent a showing of cause and prejudice, federal habeas courts may not reach the merits of
“procedurally defaulted claims
in which the petitioner failed to follow applicable state procedural rules in raising the claims.”
Sawyer v. Whitley,
— U.S. —, —, 112 S.Ct. 2514, 2518, 120 L.Ed.2d 269 (1992) (emphasis in original) (citing
Murray v. Carrier,
477 U.S. 478, 106 S.Ct. 2639, 91 L.Ed.2d 397 (1986)). We therefore do not discuss the merits of the following procedurally defaulted claims.
A.
1.
Eight argues that his death sentence is unconstitutional because the jury was not given a narrowing instruction for the “heinous, atrocious and cruel” aggravating circumstance.
See Godfrey v. Georgia,
446 U.S. 420, 100 S.Ct. 1759, 64 L.Ed.2d 398 (1980) (death penalty was unconstitutionally imposed when Georgia Supreme Court adopted overly broad meaning of “outrageously or wantonly vile, horrible and inhuman” aggravating circumstance);
Espinosa v. Florida,
— U.S. —, —, 112 S.Ct. 2926, 2927-29, 120 L.Ed.2d 854 (1992) (narrowing instruction given to jury on “wicked, evil, atrocious or cruel” aggravating circumstance was unconstitutionally vague; because, under Florida law, judge and jury are co-sentencers, neither may consider unconstitutionally vague aggravating circumstance).
Eight, however, failed to object to the omission of the narrowing instruction at the sentencing phase of his trial
and under Florida law, a claim not objected to at trial is not preserved for appeal and cannot be raised in a postconviction proceeding.
See Marek v. Singletary,
626 So.2d 160, 162 (Fla.1993) (claim that unconstitutionally vague instruction for “heinous, atrocious, cruel” aggravating circumstance was given to jury barred because defendant did not object at trial),
cert. denied,
— U.S. —, 114 S.Ct. 1869, 128 L.Ed.2d 490 (1994). Additionally, because Eight did not raise this claim in his first petition for state habeas relief or his postconviction Rule 3.850 motion, the claim is procedurally barred.
See Mills v. Singletary,
606 So.2d 622, 623 (Fla.1992) (“[h]abeas corpus cannot be used for obtaining additional appeals of issues which ... could have [or] should have ... been raised in prior postcon-viction filings”) (quotations omitted). Eight’s claim has therefore been procedurally defaulted in two separate ways.
2.
In an effort to convince this court to entertain this defaulted claim, Eight asserts that the procedural bar expired because the Florida Supreme Court’s summary denial of his second habeas petition was on the merits.
See Ylst v. Nunnemaker,
501 U.S. 797, 801, 111 S.Ct. 2590, 2593, 115 L.Ed.2d 706 (1991) (“State procedural bars are not immortal ... [and] may expire because of later actions by state courts”);
Alderman v. Zant,
22 F.3d 1541, 1549 (11th Cir.) (“should a state court reach the merits of a claim notwithstanding a procedural default, the federal habeas court is not precluded from considering the merits of the claim”),
cert. denied,
— U.S. —, 115 S.Ct. 673, 130 L.Ed.2d 606 (1994). Because we conclude that the Florida Supreme Court’s summary denial of relief cannot be said to rest on the merits of Eight’s claim rather than upon procedural default, we hold Eight’s claim to be barred.
A federal habeas court will address a procedurally defaulted claim only if the “decision of the last state court to which the petitioner presented his federal claims fairly appeared to rest primarily on resolution of those claims, or to be intertwined with those claims, and did not clearly and expressly rely on an independent and adequate state ground,” such as procedural default.
Coleman v. Thompson,
501 U.S. 722, 735, 111 S.Ct. 2546, 2557, 115 L.Ed.2d 640 (1991). We therefore must determine whether the Florida Supreme Court’s summary dismissal of Eight’s claim “fairly appear[s]” to rest on federal law.
In
Ylst,
the Court was required to determine whether unexplained decisions rested upon the merits or upon a procedural bar.
Ylst,
501 U.S. at 802-03, 111 S.Ct. at 2594. The Court looked to a prior state opinion which held Ylst’s claim to be procedurally barred and concluded that “respondent has [not] carried his burden of adducing strong evidence that one of the subsequent courts reached the merits of the federal claim.”
Id.
at 806, 111 S.Ct. at 2596. Unlike
Ylst,
however, we have no prior state decision addressing Eight’s claim that the failure to give a narrowing instruction to the jury was unconstitutional. For guidance, we therefore turn to this court’s decision in
Tower v. Phillips,
7 F.3d 206, 209 (11th Cir.1993).
In
Tower,
the petitioner filed two postconviction motions in Florida state court seeking to vacate or set aside his sentence on grounds which were procedurally barred.
Id.
at 209. The state court never ruled on his claims and petitioner filed a federal habeas petition asserting the same issues which were raised, but not decided, in the state court. We held petitioner’s claims to be procedurally defaulted because “[a]s
Coleman v. Thompson
makes clear, the Harris
presumption may not be applied in cases in which the state court opinion did not, at a minimum, discuss the federal grounds at issue .... [W]e may not assume that had the state court issued an opinion, it would have ignored its own procedural rules and reached the merits of this case.”
Id.
at 211 (footnote added).
Similarly, in this ease, although the state court summarily denied Eight’s petition, there is nothing in its disposition of the case which “diseuss[es] the federal grounds at issue.”
Id.
We thus cannot assume that had the Florida Supreme Court explained its reasoning, it would have reached the merits of Eight’s claim. Furthermore, Eight’s claim was clearly procedurally barred in two different ways.
In light of the Supreme Court’s mandate that a narrowing instruction be given when the state seeks the death penalty based upon the “heinous, atrocious or cruel” aggravating circumstance, had Eight preserved his claim for review, he would have had a strong case in the Florida Supreme Court.
Where, as here, a clearly meritorious claim is procedurally barred and the state court denies relief without opinion, “the most reasonable assumption is that ... the state court ... enforced the procedural bar.”
Id.
Because Eight has failed to show cause and prejudice sufficient to overcome the procedural bar, we do not reach the merits of this claim.
B.
The Florida Supreme Court specifically held Eight’s assertions (1) that the felony-murder aggravating circumstance is unconstitutional and (2) that the trial judge erred in not instructing the jury that it could consider Eight’s mental age as a statutory mitigating circumstance, to be procedurally barred.
See Kight,
574 So.2d at 1072 (holding claims to be procedurally barred because they could have been raised on direct appeal but were not). We therefore cannot address these claims.
See Sawyer,
— U.S. at —, 112 S.Ct. at 2518.
III.
We now turn to the claims properly preserved for habeas review and, after carefully reviewing the record, hold each to be without merit.
A.
Eight attempted to introduce evidence during the guilt phase of his trial that he lacked the mental capability to fabricate the story that he gave to the police. Outside the presence of the jury, the judge heard testimony from two defense witnesses: Dr.
Krop, a psychologist, and Dr. Miller, a psychiatrist. Following this proffer, the judge ruled the evidence to be inadmissible. Kight asserts that the exclusion of this evidence violated his constitutional rights to. a fair trial and to put forth a defense.
“We review state court evidentiary rulings on a petition for habeas corpus to determine only ‘whether the error, if any, was of such a magnitude as to deny petitioner his right to a fair trial.’”
Jacobs v. Singletary,
952 F.2d 1282, 1296 (11th Cir.1992) (citations omitted). We conclude that the trial court did not err in excluding this evidence.
The state argued at trial that this evidence should be excluded because, under Florida law, evidence of an abnormal mental condition falling short of insanity is inadmissible to negate specific intent.
See Chestnut v. State,
538 So.2d 820, 820 (Fla.1989). The trial court recognized the somewhat unique facts of this case,
and did not exclude the evidence simply because of Florida’s refusal to admit diminished capacity evidence. Rather, the trial court excluded the evidence because it concluded that whether Kight could fabricate a story is a “hypothetical question” which would “not assist the jury” but rather “would confuse the jury and not shed any enlightenment for their evaluation of the credibility issue.”
Given the confusing nature of the evidence and its limited probative value, we cannot say that the trial court erred in excluding this evidence.
Consequently, Kight was not deprived of his rights to a fair trial or to present a defense.
B.
Kight also alleges that his trial counsel, Bill Sheppard, was ineffective at the guilt and sentencing phases of his trial. We find both contentions to be without merit.
In order to prevail on an ineffective assistance of counsel claim, Kight must show that his counsel’s performance was deficient and that “there is a reasonable probability that, but for counsel’s unprofessional errors, the result of the proceeding would have been different.”
Strickland v. Washington,
466 U.S. 668, 687, 694, 104 S.Ct. 2052, 2064, 2068, 80 L.Ed.2d 674 (1984). We hold that Sheppard’s performance at the guilt and sentencing phases of Kight’s trial was not “outside the wide range of professionally competent assistance.”
Id.
at 690, 104 S.Ct. at 2066.
Kight alleges that defense counsel should have pursued an insanity defense at the guilt phase and that his failure to do so rendered his performance constitutionally ineffective. In light of Kight’s denial of complicity in the crime and his failure to come forward with evidence supporting a claim of insanity, we cannot say that his counsel was ineffective for failing to pursue an insanity defense.
See Presnell v. Zant,
959 F.2d 1524, 1533 (11th Cir.1992) (rejecting defendant’s ineffective assistance of counsel claim based upon attorney’s failure to raise insanity defense because defendant failed to come forward with evidence supporting insanity defense);
Bundy v. Dugger,
850 F.2d 1402, 1412 (11th Cir.1988) (failure to pursue insanity defense when defendant would not admit culpability in crime was not ineffective assistance of counsel),
cert. denied,
488 U.S. 1034, 109 S.Ct. 849, 102 L.Ed.2d 980 (1989).
We also find no merit in Kight’s allegation that Sheppard was ineffective because he did not adequately investigate or present mitigating evidence. Sheppard conducted a thorough investigation into mitigating evidence and hired two expert witnesses and a private investigator. Defense counsel also introduced Kight’s school records and called both Kight’s mother and sister to testify at sentencing. Given the amount of Sheppard’s preparation and the thoroughness with which he presented the evidence, we conclude that Sheppard’s performance was not deficient in any respect.
C.
Kight also asserts that the state’s failure to disclose that it made concessions to the four jailhouse inmates in exchange for their testimony at trial violates
Brady v. Maryland,
373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963), and mandates habeas relief. We hold that the state court’s factual finding that no deals were made by the government is entitled to a presumption of correctness, and thus deny relief.
The state court held an evidentiary hearing on this claim and issued a written order stating that after
viewing each witness and their demeanor on the witness stand, their frankness and lack of frankness in answering the attorneys’ questions, and the bias and prejudices brought out on some of the witnesses, ... [t]his court is satisfied beyond any doubt that the jailed inmates ... were not given any inducements for their testimony prior to or after the trial of [Kight].
Written findings of fact by a state court following an evidentiary hearing are entitled to a statutory presumption of correctness unless a petitioner can establish that one of the statutory exceptions exists.
See
28 U.S.C. § 2254(d). Kight asserts that the district court should not have presumed the state court’s findings to be correct because the factual dispute concerning the
Brady
violation was not fully resolved by the state court and because the court’s conclusions were not supported by the record.
We do not agree.
After reviewing the transcript of the evi-dentiary hearing, we cannot say that the court’s findings were not supported by the record or that the state court failed to fully resolve Kight’s constitutional claims.
Thus, the state court’s finding that there were no undisclosed deals is entitled to a presumption of correctness and the district court correctly declined to hold an evidentiary hearing.
See McBride v. Sharpe,
25 F.3d 962, 971 (11th Cir.1994) (en banc) (“In a federal habeas case, a written finding made by a state court of competent jurisdiction after a hearing on the merits of a factual issue in a proceeding to which the petitioner and the state were parties shall be presumed to be correct unless a statutory exception applies.”),
cert. denied,
— U.S. —, 115 S.Ct. 489, 130 L.Ed.2d 401 (1994).
D.
Eight also argues that the statements which he gave detectives on December 17, 1982, were erroneously admitted at his trial in violation of his Fifth and Sixth Amendment rights to counsel. When Eight was taken to the property room, he told Detective Weeks that he was not afraid of the chair. In response, Weeks asked Eight “what chair are you talking about” and Eight began to describe Butler’s murder. Eight was promptly read his rights and executed a waiver. He then gave another detective a formal statement. He asserts that these statements were taken in violation of his Fifth and Sixth Amendment rights to counsel and thus should have been suppressed at trial.
We disagree.
The Sixth Amendment guarantees an accused the right to counsel; this right, however, “does not attach until a prosecution is commenced.”
McNeil v. Wisconsin,
501 U.S. 171, 175, 111 S.Ct. 2204, 2207, 115 L.Ed.2d 158 (1991). For purposes of the Sixth Amendment right to counsel, a prosecution commences “at or after the initiation of adversary judicial criminal proceedings— whether by way of formal charge, preliminary hearing, indictment, information, or arraignment.”
United States v. Gouveia,
467 U.S. 180, 188, 104 S.Ct. 2292, 2297, 81 L.Ed.2d 146 (1984) (citation omitted).
When Eight gave the statements to the police about the Butler murder, prosecution had not yet commenced against Eight with respect to this crime. Although prosecution had begun against him with respect to the McGoogin robbery, the “Sixth Amendment right [to counsel] ... is offense-specific.”
McNeil,
501 U.S. at 175, 111 S.Ct. at 2207.
In addition to a Sixth Amendment right to counsel, the Supreme Court held in
Miranda v. Arizona,
384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966), that “[a] suspect subject to custodial interrogation has the right to an attorney and to have counsel present during questioning, and the police must explain this right to him before questioning begins.”
Davis v. United States,
— U.S. —, —, 114 S.Ct. 2350, 2354, 129 L.Ed.2d 362 (1994). The Fifth Amendment right to counsel is not offense-specific; the suspect must, however, invoke this right by unambiguously requesting counsel. .
See id.
at —, 114 S.Ct. at 2357.
Upon his arrest for the McGoogin robbery, Eight did not invoke his Fifth Amendment right to counsel.
Rather, Weeks testified that Eight stated that he “knew his rights and ... did not want to talk to me”; Eight never used the “word lawyer, attorney or mouthpiece.” Thus, Eight’s statements were properly admitted at trial.
E.
Eight’s final assertion that the trial judge erred in failing to find that his mental retardation and childhood abuse were mitigating factors is also without merit.
“Acceptance of nonstatutory mitigating factors is not constitutionally required; the Constitution only requires that the sentencer
consider
the factors.”
Atkins v. Singletary,
965 F.2d 952, 962 (11th Cir.1992) (emphasis in original). When defense counsel has been given an opportunity to present mitigating evidence but the sentencer declines to find mitigating factors, our review is “highly deferential.”
Id.
Thus, the “[t]rial court’s findings on mitigating factors are presumed to be correct ... and will be upheld if they are supported by the record.”
Id.
The defense presented its evidence at the sentencing phase of Eight’s trial. In the written judgment and sentence, the court explained its reasons for rejecting each of the statutory mitigating factors. It is clear from
this order that the court specifically considered evidence that Eight was “mentally retarded” and “was an underprivileged [and abused] child,” but declined to find these factors to be mitigating.
After carefully reviewing the record, we cannot say, in light of the other evidence, that the judge erred in failing to find Eight’s borderline mental retardation and abused childhood to be mitigating factors.
See id.
(no error when “trial judge fully considered all the supposedly mitigating factors offered by [defense] but, in light of the other evidence presented by the state, refused to accept most of these factors”).
IV.
For the forgoing reasons, we AFFIRM the district court’s order denying Eight’s petition for a writ of habeas corpus.