The US government has charged a member of a Russian ransomware group known as Karakurt, as reported earlier by BleepingComputer. In a press release on Tuesday, the Department of Justice claims 33-year-old Deniss Zolotarjovs of Moscow, Russia, conspired to commit money laundering, wire fraud, and extortion.

As outlined in the criminal complaint, the FBI alleges Karakurt stole and threatened to auction sensitive data from several companies throughout the US. The complaint pins Zolotarjovs as the hacking group’s negotiator of “cold case extortions,” in which victims don’t respond with a ransom following an attack, according to BleepingComputer.

Karakurt, which has been linked to the prolific Russian ransomware group Conti, carried out a cyberattack on an Oklahoma hospital, where it threatened to auction off patient data, and also targeted a hospital in Texas. Last year, the group claimed to have stolen the social security numbers of 150 million people from a company called Officeworks.

A bulletin from the US Cybersecurity and Infrastructure Security Agency says Karakurt has been known to contact victims’ employees, business partners, and clients “with harassing emails and phone calls to pressure the victims to cooperate.” It also operated a leaks and auction website.

Law enforcement in the Eastern European country of Georgia arrested Zolotarjovs last December and extradited him to the US earlier this month. The DOJ says Zolotarjovs is the first alleged Karakurt member to be arrested and extradited to the US.