U.S. investigators have recovered millions of dollars in cryptocurrency that Colonial Pipeline paid hackers last month to end a ransomware attack on its systems.

Deputy Attorney General Lisa Monaco announced Monday afternoon that the Department of Justice “found and recaptured the majority of the ransom” paid to the DarkSide network, the group responsible for the attack.

Paul Abbate, the deputy director of the FBI, said the bureau successfully seized the ransom funds from a bitcoin wallet that DarkSide used to collect Colonial Pipeline’s payment.