District court convictions for first-degree murder and sexual penetration of a dead body reversed and case remanded for new trial. Trial court’s exclusion of extrinsic evidence to prove potential bias of State’s witness against Defendant was reversible error, not harmless error. Although a trial court had broad discretion to control cross-examination attacking a witness’s credibility, that discretion was narrowed when bias or motive was to be shown. Unless materially related to the case and admissible on other grounds, extrinsic evidence of prior bad acts or inconsistent statements is always collateral and, therefore, inadmissible to attack credibility. But, extrinsic evidence to prove a witness’s bias interest, corruption, or prejudice is never collateral and was admissible for impeachment. Even though Defense failed to recall the State witness for possible impeachment without the use of extrinsic evidence, Defendant preserved right of appeal where Defendant crossed the witness on the relevant matter outside the presence of the jury and where the trial court made a definitive exclusionary ruling.
Brown, Keith, "Summary of Lobato v. State, 120 Nev. Adv. Op. No. 57" (2004). Nevada Supreme Court Summaries. 650.