It is a federal crime to tamper with a witness, victim, or an informant.
Witness tampering can be committed in several ways, including harassing, intimidating or making threats to a witness to dissuade them from providing testimony or documents, or from attending a trial or other proceeding. It includes killing or attempting to kill a person who might furnish information or documents to federal officials in order to prevent such disclosure.
Witness tampering can consist of misleading conduct, such as hiding a witness from authorities to prevent her testimony at a criminal trial, or making false statements to convince another person to lie. Attempts to silence a witness through cajolery and bribery are also considered witness tampering. So is instructing someone not to cooperate with a government investigation and to deny any involvement in the illegal activity.
It is an affirmative defense to the crime of witness tampering that the conduct consisted solely of lawful conduct and that the defendant's sole intention was to encourage or cause the other person to testify truthfully. It is the defendant's burden to prove this defense by a preponderance of the evidence.
Penalties under the federal witness tampering statute range from up to one year for less serious violations, to life imprisonment or the death penalty for a killing.