United States v. Harvey
United States Court of Appeals for the Second Circuit
547 F.2d 720 (2d Cir. 1976)
Harvey (defendant) was charged with bank robbery. Priscilla Martin, the only eyewitness who could identify him, had known Harvey for nineteen years and once lived with him. On cross-examination she denied ever accusing him of fathering and failing to support her child, and denied threatening revenge to his mother. Harvey then tried to call his mother to testify that Martin had made those accusations and the threat, to show Martin's bias, but the trial judge excluded the testimony as collateral. The jury convicted Harvey, and he appealed.
Whether a witness's bias is a collateral issue that bars a party from introducing extrinsic evidence to prove it, once the witness has denied the bias on cross-examination.