Is there any case law where a prosecutor has been found guilty of misconduct in questioning a defendant's credibility?

Defendant complains in particular that the prosecutor attempted to impeach his credibility by asking if defendant had changed his appearance because he was to appear before the jury. This, he suggests, was an appeal to passion and prejudice, but People v. Kirkes (1952) 39 Cal.2d 719, 724, 249 P.2d 1, on which he relies, hardly supports that argument. In Kirkes the prosecutor, stating facts not in evidence, had asserted personal knowledge of the defendant's guilt, implied he would not have prosecuted had he not believed in the defendant's guilt, and pictured the defendant as a person who would kill again to cover his crime and prevent witnesses from testifying. While we may question the relevance of defendant's possibly improved appearance to assessing his veracity, the misconduct, if any, in the line of questioning could easily have been cured by an admonition had an objection been made. ⁴²