Just deepens the mystery.
Okay, so he planned it all meticulously for 12 months.
And he was meticulous in covering his tracks.
But why be meticulous in covering your tracks when you're on a suicide mission? He had to have known that he was gonna die, so avoiding leaving clues and escaping the law would be irrelevant.
And we still don't know why he did it.
He may, or may not, have conspired with some one, or some group.
The article says that one of his two email addresses to correspond with weapons sellers might have been controlled by some second party ( the mob? ISIS?).
But if it were terrorism they would gone public by now. That's the whole point of terrorism. To send a message.