Can one witness say if another is lying?

Jay Leiderman
By: Jay Leiderman
April 05 2016


The defendant hereby objects to questions directed at one witness, or at himself, concerning the veracity of another witness. It is improper for the prosecutor to question one witness concerning the veracity of another, such as “if witness X said Y would he be lying or mistaken?” Asking a defendant whether the police officer is lying can be prosecutorial error. A lay witness’s opinion about the veracity of another person’s statements is inadmissible and irrelevant on the issue of the credibility of those statements. (People v. Zambrano (2004) 124 Cal.App.4th 228.) In other words, typically, it is error for a prosecutor to ask any testifying witness whether any other witness lied either during an interrogation or on the stand, because credibility determinations are for the jury to make, and it is improper as either expert or lay opinion testimony. (People v. Melton (1988) 44 Cal.3d 713, 744; People v. Sergill (1982) 138 Cal.App.3d 34; People v. Foster (2003) 111 Cal.App.4th 379, 384-385; United States v. Sanchez (9th Cir. 1999) 176 F.3d 1214, 1220-1221; United States v. Henke (9th Cir. 2000) 222 F.3d 633, 643; United States v. Geston (9th Cir. 2002) 299 F.3d 1130, 1136-1137; United States v. Combs (9th Cir. 2004) 379 F.3d 564, 572-575.) There are qualifications of this rule in People v. Chatman (2006) 38 Cal.4th 344. “Counsel should not ask one witness to comment on the veracity of the testimony of another witness.” (United States v. Boyd (D.C. Cir. 1995) 54 F.3d 868, 871; United States v. Richter (2nd Cir. 1987) 826 F.2d 206, 208, holding that a prosecutor is guilty of misconduct when the defendant is forced to testify that an FBI agent was either mistaken or lying.) “We have held that it is reversible error for a witness to testify over objection whether a previous was telling the truth.” (United States v. Sanchez-Lima (9th Cir. 1998) 161 F.3d 545, 548, a case that is cited approvingly in People v. Zambrano supra. at 242.) “It is the jurors’ responsibility to determine the credibility … Testimony regarding a witnesses’ credibility is prohibited unless it is admissible as character evidence.” (Sanchez-Lima supra. at 548, citing United States v. Binder (9th Cir. 1985) 769 Fed.2d 595, 602.) Here, MR. BROWN asks the court to exclude statements concerning other witnesses’ veracity, since it is typically error for the prosecutor to ask such questions in the first place.


At Jay Leiderman Law, we have proven results over years of practice, and we are uniquely qualified to represent you in your time of need. We are situated in Ventura, California but we handle cases throughout the state. We have the expertise, experience and skill to handle numerous types of legal matters.  Jay Leiderman is one of only a few CERTIFIED CRIMINAL LAW SPECIALISTS in the area.  He handles every kind of criminal law case. He is famous for defending medical marijuana cases and computer hacking cases, though the bulk of his practice is a generous mix of those cases plus serious felonies and misdemeanors.  Read more at his Wikipedia page: or his homepage

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Jay Leiderman addresses the crowd at a fundraiser for journalist Barrett Brown and hacktivist Jeremy Hammond in New York City

This post does not create an attorney-client relationship and does not constitute legal advice.  Moreover, the law changes over time.  Always consult an attorney before determining what motion s to file and what the current law is as to any particular topic.

Criminal defense attorney and author Jay Leiderman, a California State Bar Certified Criminal Law Specialist can be contacted through the contact page of this website:

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