If this is true I hope the FBI locates the person/persons that sent such a letter and prosecutes them to the fullest extend of the law. That is not how we do things here.
I agree. And who knows what the motive really is. This may just be some vigilante who is more bark than bite. Or it may be some insidious attempt by some third party to implicate the US in terroristic activities. Either way, it don't play.