I wasn’t thinking about the US particularly, but it appears to be the case in some states. e.g., Texas
(quote has modified formatting)
Sec. 38.171. FAILURE TO REPORT FELONY.
(a) A person commits an offense if the person:
- (1) observes the commission of a felony under circumstances in which a reasonable person would believe that an offense had been committed in which serious bodily injury or death may have resulted; and
- (2) fails to immediately report the commission of the offense to a peace officer or law enforcement agency under circumstances in which:
- (A) a reasonable person would believe that the commission of the offense had not been reported; and
- (B) the person could immediately report the commission of the offense without placing himself or herself in danger of suffering serious bodily injury or death.
(b) An offense under this section is a Class A misdemeanor.
This is a bit more specific than what I claimed in that you must have observed the crime.
More generally I was thinking about all the associated crimes, like depending on context you might get charged with concealing a death, or aiding and abetting.
Also I think in some places it’s a crime not to report a death.