It's hard to say. The paypal went to an email address and the bomber listed a physical return address on the package but there was no note inside indicating an email address.
Essentially there is no way to ever learn this answer I'm afraid.
Sounds like Tom Brady's deflategate story going on here. Horseshoe wins!!!
Mr. Simpson, don't you worry. I saw an episode of Matlock in a bar last night. The sound was down, but I think I got the gist of it.