How to Convince the Court Someone Is Lying

Witness swearing on bible telling the truth
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There's a pretty good chance you aren't Perry Mason, Denny Crane or even Saul Goodman, which means that it isn't usually in your best interests to try to convince any type of court that someone is lying with your own self-represented monologue, no matter how impassioned, truthful or TV-ready that monologue may be. While your lawyer will lead the charge as always (that's why you hired her), you can help fight courthouse lies by packing your mental quiver full of knowledge about the standard procedures American courts have in place to fight all manner of untruths.

It Starts With Testimony

Hearing someone knowingly lie on the stand can be infuriating, but the simplest way to catch a witness lying is to provide a contrary testimony that calls those lies into dispute. This, of course, can be done in criminal, civil, commercial, family or probate cases. While it remains up to the court to hear and evaluate both sides of the story, a conflicting testimony that strongly calls the lie into question may cause the judge to determine that the untruthful witness is adverse or hostile. At the very least, it can call the lying witness' credibility into question, which is a step in the right direction for your case.

Similarly, if you observe lies in a witness testimony, you can ask your attorney to cross-examine the witness on a specific point. Let your lawyer know which part of the testimony you believe to be a lie and he can focus the cross-examination on questions that reveal inconsistencies in that part of the testimony. Oftentimes, the trick to this is honing in on highly specific details, which a lying witness may not be able to readily provide. With these inconsistencies or missing details revealed to the court, the jury may decide to discard the witness' testimony in whole or in part.

The Power of Evidence

When it comes to testimony, it's ultimately up to the jury to decide who and what to believe, often leading to he-said-she-said situations. Evidence, on the other hand, is a much more definitive tool for disproving lies in the courtroom.

Though it's not always available, you may be able to swat down witness fibs with hard, objective proof. Pairing surveillance footage, photos, hard-copy records or audio recordings with a conflicting witness' testimony is often enough to turn the court in your favor. In cases of bodily violence, for instance, you may obtain a physical examination from a doctor to collect proof of specific instances of abuse. Other forms of evidence to consider include social media, emails, bank statements and transaction records.

More to Know

In some cases, you may request that the judge give the jury instruction in regards to specific evidence or testimony that you find lacks credibility. This instruction enables the jury to give each piece of evidence presented its own "weight" in regards to credibility when making their decision.

While lying under oath is legally defined as the punishable crime of perjury, when perjury occurs in non-criminal court, a prosecutor must take an interest in the case to try the accused of perjury. As you might guess, this is an exceedingly rare situation. The unfortunate reality is that – while false testimony, evasion and withholding evidence can cause a witness to be held in contempt of court – most perjury goes unpunished (and in the very rare cases that one is tried, the sentence is often a light one, such as the probation sentence given as punishment in California's People v. Berry case of 1991). As such, it's often more effective to rely on testimony and evidence to disprove lies rather than pursue or file perjury charges.


  • Trust the time-tested legal system and rely on methods such as testimony, evidence and examination to disprove lies in a court of law.

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