concurring in part and concurring in the result:
I agree that appellant’s convictions must be reversed on the “corruption bias” *858ground set forth in part III of the court’s opinion. The trial judge’s erroneous conclusion, urged by the prosecutor, that Brown’s interaction with the witness or witnesses in the unrelated homicide case was essentially collateral denied appellant the chance to adduce extrinsic evidence potentially important to judging his veracity in this case when he rehabilitated a key government witness. The court persuasively explains why that is so, and no more is necessary to resolve this appeal. I cannot understand the court’s insistence, nonetheless, on exploring issues of a possible due process violation under Mooney/Napue principles. .Those issues are complex enough that ultimately the court itself does not decide the due process question, and even if it had done so, the conclusion would have no bearing on our decision to reverse.