They read him his rights, but didnt arrest him? This whole story sounds like a load of crap.
"If we were going to arrest you, we'd have to inform you that you have the right to remain silent, and that anything you say can and will be used against you in a court of law... but we're not going to arrest you, we just want to look around your apartment and maybe shoot your dog."
The account as he described it is total BS. Some of his previous posts are disturbing in a mentally ill, unabomberish sort of way though. He's yammered on about hangings, and otherwise said some pretty bizarre disjointed stuff. If he really got a visit from the FBI or SS, it could be because he was contributing very inflammatory stuff on other websites since FR is well moderated.