concurring in part and dissenting in part.
I respectfully dissent from that part of the majority opinion which reverses Foster’s sentence of death because the sentence was properly entered by the trial judge pursuant to the jury’s recommendation after both defendants received a fundamentally fair, joint trial.
Foster failed to prove that she had been prejudiced by the joint trial. RCr 9.16. *684There has not been a “clear showing of an abuse of discretion” in regard to the trial court’s refusal to sever the trials notwithstanding the trial court’s previous decision to grant severance. Epperson v. Commonwealth, Ky., 809 S.W.2d 835, 838 (1991). As recognized by the majority, “there is a strong policy in favor of joint trials when charges will be proved by the same series of acts.... ” United States v. Blakeney, 942 F.2d 1001, 1010 (6th Cir.1991). In this case, it is admitted by Foster and Powell that they committed the murders of the victims. Each of the five victims was killed by the defendants over the course of the same evening with the defendants stopping twice to find bullets, and once to repair the gun which they were using to shoot the victims. Foster and Powell were seen with one another throughout the evening and were eventually arrested together while at the hospital. The only question, as Powell recognized in her opening statement on the first day of trial, was not whether the defendants were guilty, but what penalty the jury would impose upon them for their outrageous and senseless behavior. Under these facts, and for the purpose of judicial economy, the trial judge properly held a complete joint trial.
Foster also failed to prove that she and Powell had antagonistic defenses, or that the evidence as to one defendant tended to directly incriminate the other. Tinsley v. Commonwealth, Ky., 495 S.W.2d 776, 780 (1973). Prior to and during trial, Foster and Powell admitted their respective participation in the murders, and there can be no complaint now that the evidence presented at trial by the Commonwealth or a co-defendant directly incriminated one defendant over the other.
The “mitigation” of duress raised by Powell in the penalty phase of the joint trial was not antagonistic to the mitigation evidence presented by Foster. A potentially antagonistic defense is only one of the factors for the trial judge to consider in determining whether to grant a severance. Epperson, supra. “The movant must establish that the jury would be unable ‘to separate and treat distinctively evidence that is relevant to each particular defendant on trial.’ ” Blakeney, supra, at 1011, citing United States v. Gallo, 763 F.2d 1504, 1525 (6th Cir.1985). “Even if the movant establishes some potential jury confusion, this confusion must be balanced against the need for speedy and efficient trials.” Id. Moreover, “We presume that the jury will be able to sort out the evidence applicable to each defendant and render its verdict accordingly.” Id., citing United States v. Horton, 847 F.2d 313, 317 (6th Cir.1988).
The jury in this case was able to ponder the evidence presented by the defendants in support of their respective mitigating claims in arriving at an appropriate sentence. It is within the exclusive province of the jury to determine from the evidence whether one defendant is more culpable than his or her co-defendant, and thereafter to apply this conclusion to their respective sentences. For the first time, a majority of this Court applied the severance standards found in Tinsley, supra, to mitigating evidence and has unintentionally made it virtually impossible for a trial court of this Commonwealth to conduct a joint trial where one co-defendant alleges commission of a crime under duress.
The trial judge properly allowed Powell and the Commonwealth to cross-examine Foster’s experts, Dr. Noelker in the guilt phase and Lane Veltkamp in the penalty phase, about the specific acts of charged and uncharged misconduct which the experts had used in formulating their respective opinions. It is unchallenged by the majority that the Commonwealth may fully inquire into, on cross-examination, evidence used by an expert in forming his opinion. 31 Am.Jur.2d, Expert and Opinion Evidence § 92. This inquiry must include bad acts where the expert has, as in this case, heavily relied upon the knowledge of bad acts in formulating an opinion. Otherwise, the Commonwealth has been effectively hindered in its cross-examination of a defendant’s expert witness.
The bad acts were admissible in both the guilt and penalty phase of the defendants’ joint trial. It is undisputed that Foster *685herself first brought her character into issue through the testimony of Dr. Noelker, and later in the penalty phase, through her videotaped testimony which allowed Foster to testify at the trial without being cross-examined. The bad acts used by Powell in supporting her mitigating claim of duress were cumulative to the bad acts which Foster herself had already admitted on direct examination. It should be noted that Powell had cross-examined Veltkamp about uncharged misconduct, and not the Commonwealth, and therefore, the same rules about inquiry into a defendant’s character do not apply.
The trial judge did not abuse his discretion when he admitted the Foster letters in support of Powell’s mitigation. The probative value far outweighed the prejudicial effect which the contents may have had on Foster’s mitigation. The jury properly considered the defendants’ respective mitiga-tions and reached a just verdict.
I do not believe any reversible error occurred in the admission of Powell’s expert testimony on the battered wife syndrome. The expert specifically stated that the relationship between Foster and Powell could be “compared” to the battered wife syndrome. The expert did not state that Powell was a battered wife, but merely tried to explain why Powell did not try to run from Foster on the night of the murders. The admission of the testimony was not error because the probative value to Powell far outweighed the alleged prejudicial effect to Foster. No abuse of discretion occurred.
The sentence entered by the trial court against Foster should be affirmed. I concur with the balance of the majority opinion which affirms the convictions of both appellants and Powell’s sentence.