Legal Question in Criminal Law in California

Re: Prelim witnesses in capital murder trial

Defense counsel (or a defendant in pro per) can move for an order excluding witnesses from the courtroom, but if no such motion is made then the witnesses need not be excluded.

It sounds from your question as if a witness testified and then remained present while a subsequent witness testified, which usually would not be a problem anyway. The potential for a problem arises when a witness testifies *after* hearing the testimony of another witness. Even then, it is not the kind of error that results in an automatic dismissal or mistrial. Instead, it simply provides ground for impeachment (in other words, a reason to question the accuracy of that witness's testimony).

When and if this witness testifies at trial, the defendant can cross-examine him and bring out the fact that he heard the other witness testify at the prelim. The jury likely won't care much unless there is reason to believe the witness is trying to modify his testimony in order to make it consistent with the other witness's statements.

In some cases, there might be a reason why it is unusually important to prevent one witness from hearing another's testimony. If this is such a case and the defense counsel failed to seek an order excluding witnesses, then his action might be deemed ineffective assistance of counsel. Even then, however, it will only be important if the result likely would have been different without the mistake.

Likewise, if the judge either improperly denied a motion to exclude or granted such a motion and then failed to have the witness kept out of the courtroom, the error will only be significant if it likely affected the result.