Well that was quick:
http://www.cnn.com/2013/04/23/us/ric...html?hpt=hp_t1
Looks like the Elvis impersonator might have been set up by somebody that doesn't like him. I guess they weren't satisfied to make a phony "SWAT" emergency call on the guy.
Of course, maybe the FBI should have suspected that the name "Paul Kevin Curtis" and the return address on the letters might have been, you know, just a little too easy.
Just sayin'.