Kickass Torrents is said to have stolen "more than $1 billion in profits from the US entertainment industry"
Authorities in the US say the alleged owner of the 'most-visited' illegal file-sharing site on the internet has been arrested.
Artem Vaulin (30) of Kharkiv, Ukraine was arrested in Poland over allegations he owns the Kickass Torrents (KAT) site.
The US Justice Department says it is now seeking to extradite Mr Vaulin.
He has been charged with criminal copyright infringement.
A Chicago court also ordered the seizure of one bank account and seven domain names associated with "the alleged KAT conspiracy".
US authorities stress that the charges and allegations "contained in the complaint are merely accusations. The defendant is presumed innocent until and unless proven guilty."
Kickass Torrents is reported to receive around 50 million unique visitors a month.
Authorities say the site enables users to "illegally reproduce and distribute" millions of films, music recordings, video games and other media.
Executive Associate Director Peter T Edge of Homeland Security Investigations said: "Artem Vaulin was allegedly running a worldwide digital piracy website that stole more than $1 billion in profits from the US entertainment industry.
"With the cooperation of our law enforcement partners, we will continue to aggressively bring to justice those who enrich themselves by stealing the creative work of US artists.”
TorrentFreak reports the KAT site 'disappeared' shortly after the news of Mr Vaulin's arrest.