Murder on a webcam... - What do i do?

[Is Don on the phone?]

I think I would disavow any knowledge until I was confronted by the feds.

Title 18, United States Code, Section 4:
Whoever, having knowledge of the actual commission of a felony cognizable by a court of the United States, conceals and does not as soon as possible make known the same to some judge or other person in civil or military authority under the United States, shall be fined under this title or imprisoned not more than three years, or both

Not a good plan, because the feds can charge you anyway.