Who is behind Kickass Torrents?
Mr. Vaulin is alleged to own Kickass Torrents or KAT. 
A Ukrainian alleged to be the ringleader of the world’s biggest online piracy site, Kickass Torrents, was hit with U.S. criminal charges for distributing over $1 billion worth of illegally copied films, music and other content.

The Justice Department unveiled a criminal complaint against Artem Vaulin, 30, of Kharkiv, Ukraine, who was arrested in Poland earlier in the day and is being sought by U.S. authorities for copyright infringement, money laundering and other charges.

About Kickass Torrents 
KAT, which distributes films, video games, television programs, music and other electronic media, is estimated to be the 69th most frequently visited website, according to a Justice Department statement. “Vaulin is charged with running today’s most visited illegal file-sharing website, responsible for unlawfully distributing well over $1 billion of copyrighted materials,” said Assistant Attorney General Leslie Caldwell.

How the crime was made possible?
“In an effort to evade law enforcement, Mr. Vaulin allegedly relied on servers located in countries around the world and moved his domains due to repeated seizures and civil lawsuits. His arrest in Poland, however, demonstrates again that cybercriminals can run, but they cannot hide from justice.”

Action sought by US Government
U.S. officials will seek to extradite Mr. Vaulin to face charges filed in federal court in Chicago, which ordered the seizure of one bank account and seven domain names associated with the file-sharing website.