Where did Joe's powers come from?  Even from the story it could've been either from what I could see.  I guess we do see that power corrupts.  I was curious if he may have caused the deaths of his parents as well, but that wasn't spoken about in the story.

Then again, during his last act he mentions memory tricks, so it's possible that he had no powers at all, just good observational skills and memory (like the BBCs Sherlock).