Isn't this Misprision of a Felony? I think this roommate may have just gotten himself a prison sentence.
Misprision
Neat word.
Nope. Misprision of felony requires a felony in the first place, and six months ago, there wasn't one.
But, anybody who knows a dope smoker (and I'm NOT looking at you, DiogenesLamp) who also possess a firearm, that hasn't turned the felon in to some judge or other person in civil or military authority under the United States, has committed misprision of felony (18 USC 4), the underlying firearm possession felony being 18 USC 922(g).