During Evans’ trial for robbery, the trial court became aware that a juror had failed to fully disclose her potential bias against the prosecution. Over the objections of both parties, the trial court dismissed the juror after concluding that she could not be fair. Both alternates had already been dismissed, so the court declared a mistrial. When the prosecution refiled the charges, petitioner moved to dismiss on double jeopardy grounds. The trial court denied the motion, and petitioner filed this petition for writ of mandate. Here, the appellate court granted the writ and ordered the superior court to grant the motion to dismiss. Petitioner’s jury was dismissed without his consent and without legal necessity. The juror was not excused because she could not serve but because the court thought she was biased. If a defendant wishes to proceed with the biased juror, he or she is entitled to do so. After jeopardy has attached, no mistrial can be declared except where the defendant consents or in cases of legal necessity.