Holy smokes, what a bump!
Anyway, since it happened a long time ago don't you think that he has already covered his tracks and disappear?
I saw his ID went online briefly on Sept 5th 2017, but that's it.
Can't you track his home address? I thought every letter sent has sender address in it along with receiver address.

You also might want to create a new topic on either Scam Accusation or Investigation, people would be all over your request with a 50% rewards, granted that we can find the guy