Is it improper for a prosecutor to ask a witness, "When you gave your statement to that detective, did you tell the truth?"

Next, defendant contends it was improper for the prosecutor to ask a witness, "When you gave [your] statement to that detective, did you tell the truth?" He cites no authority for the assertion of error, and he concedes the question was asked and answered without objection. Finally, defendant alleges the prosecutor erred by rhetorically asking him if he had "a personal stake in the outcome of this case." Although an objection was made, it was correctly overruled. "'It is always proper for a party against whom a witness has given damaging testimony to show out of the mouth of the witness himself, if he can, or by other sources, if necessary, that such witness has an unusual interest in the outcome of the case.'" (People v. Pierce (1969) 269 Cal.App.2d 193, 200.) A prosecutor may question a witness regarding "'prominent motives for untruthful testimony,'" including "'interest in the suit[,] which necessarily tends to [show] bias.'" (People v. Vanderburg (1960) 184 Cal.App.2d 33, 41, italics omitted.)