TL;DR; Feds pose as an advertised on KAT.CR and finally find the bank account associated with this torrent website and in the process Apple, Facebook, GoDaddy and coinbase helped in finding the owner that lead to his arrest.
More recent records show that an IP-address linked to KATs Facebook page was also used to access Vaulins Coinbase account, suggesting that the Bitcoin wallet also assisted in the investigation.
https://torrentfreak.com/can-kickasstorrents-make-a-comeback-160721/the strangest part of this is using Coinbase as bitcoin wallet which i don't really get. WHY

Most people did not really pay attention to the fact that bitcoin addresses and such can be traced. People do not realize that all bitcoin transactions can be traced back to the mac address and the internet ip address in which it was all accessed. It could also have been a setup for him. IDK, but good luck and I am glad i do not use that site.