KickassTorrents (KAT) is the biggest pirate site in the world, hosting thousands of torrents covering the biggest movies and music in the world. The 30-year-old Ukrainian founder, Artem Vaulin, was arrested in Poland today, and the US government has requested his extradition.

A court in Chicago has also ordered the seizure of bank accounts and domain names related to the site.

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Vaulin has been formally charged with conspiracy to commit criminal copyright infringement, conspiracy to commit money laundering, and criminal copyright infringement. As of the moment, the main KickassTorrents site appears to be down worldwide.

In a press release given to Ars Technica, the Department of Justice said that they’d chased Vaulin around the world trying to capture him.

“Vaulin is charged with running today’s most visited illegal file-sharing website, responsible for unlawfully distributing well over $1 billion of copyrighted materials. In an effort to evade law enforcement, 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.”

An undercover IRS agent allegedly pinned KAT’s bank account by going undercover to buy and ad on the site. The agent bought a “faster download” ad for five days, at a rate of $300 per day. Banner ads were priced at thousands of dollars, allowing a witness to estimate KAT’s annual advertising revenue at $16 million.

That estimate may be way off, however. Pricing illegal online activities is difficult, as proven by the trial of Silk Road founder Ross Ulbricht. In that case, the prosecution’s estimate of revenue was off by an entire order of magnitude.

Based on the DOJ press release, the case against Vaulin seems to be quite clear-cut. Assuming the extradition goes through, this will be a landmark first case against the head of a major pirate site. But if history has taught us anything, it’s that there will be three new torrent sites springing up in KAT’s place tomorrow.