From GOOGLE's Gemini
Not reporting a murder you witness is most commonly referred to as a failure to report a felony or, if you actively take steps to conceal the crime, misprision of a felony or being an accessory after the fact. [1, 2, 3]
The exact legal term and consequences depend on state laws and your specific actions:
Failure to Report: In most U.S. jurisdictions, a bystander who is not involved in the crime has no general legal duty to rescue or call the police. However, several states have mandatory reporting laws where failing to report a high-level felony (like murder) can result in criminal charges. [1, 2, 3, 4, 5]
Misprision of a Felony: This applies if you not only know about the murder but take active steps to conceal it or prevent its discovery. Under federal law (18 U.S. Code § 4), this is a felony punishable by up to three years in prison. [1, 2, 3, 4]
Accessory After the Fact: If you help the killer avoid apprehension, hide evidence, or provide a false alibi, you can be charged as an accomplice or accessory to the murder. This carries severe penalties, often making you face the same level of prison time as the murderer. [1, 2, 3, 4, 5]
