Can I Tamper With My Witness?

What if the judge didn’t tell me not to?

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The death penalty trial of Zacarias Moussaoui may be abandoned, prosecutors told the judge on Wednesday. The judge had decided to exclude a major component of the government’s case the day before, after she learned that a prosecutor had tampered with several witnesses in direct violation of her court order. Does a federal judge really need to tell lawyers not to tamper with witnesses?

Not exactly. Title 18, Section 1512 of the U.S. Code makes it a crime to tamper with a witness, a victim, or an informant. As a result, a lawyer doesn’t need a judge to tell her that she can’t kill, threaten, intimidate, or “corruptly influence” a witness so as to prevent or alter his testimony. (The law against obstruction of justice can also apply to cases of witness tampering.) But judges do have to be explicit in their proscription of less flagrant practices, like excessive witness “coaching.”

Coaching can be a problem if it causes the testimony of one witness to be influenced by the testimony of another. A prosecutor might fish for a certain version of events by presenting her witness with other evidence from the case. If she tells the witness what other people have already said in court, the witness may change his story to match.

Judges can try to keep this from happening by sequestering the witnesses. That doesn’t mean that a bailiff will confiscate their newspapers and lock them in a hotel—but it does mean that the lawyers can’t tell them what other witnesses are saying at the trial. (In the Moussaoui case the witnesses were instructed to avoid media accounts of the trial as well.) Either side can request one of these sequestration orders under Rule 615 of the Federal Rules of Evidence, or the judge can issue it at her own discretion. In fact, it’s common practice for a judge to sequester the witnesses at the start of a criminal trial.

What if a prosecutor coaches the witness a little bit too much before the trial even starts? Lawyers can start prepping someone for the stand well before the judge has a chance to issue a sequestration order. That means they can present their witness with documentary evidence that they plan to introduce in court, or they can tell him what their other witnesses are going to say under oath. These practices wouldn’t necessarily run afoul of Rule 615, nor would they amount to criminal tampering under section 1512. But lawyers are under an ethical obligation to avoid coaching a witness in such a way that would distort his testimony. A prosecutor who violated this code might not face criminal and civil contempt citations (like the ones threatened for the Moussaoui blunder), but she could find herself in front of a state ethics committee.

Bonus Explainer: Can the government appeal the judge’s decision to exclude evidence? Yes. Under 18 U.S.C. Section 3731, prosecutors can appeal a district court decision to suppress evidence as long as they can demonstrate that the excluded evidence is vital to their case and that they’re not just trying to delay the trial. They’ll be stuck if the appeals court fails to act: If the missing evidence sinks their case—and the Moussaoui jury rejects the death penalty—they won’t be able to mount another appeal.

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Explainer thanks Dan Richman of Fordham University.