The U.S. Bureau of Prisons said in a news release Saturday that the FBI would investigate the apparent suicide.
Authorities said Epstein was found unresponsive in his cell early Saturday morning. He was transported to a hospital for treatment and he was pronounced dead there, officials said.
Several lawmakers have called for answers in Epstein's death after he was reportedly put on suicide watch in late July following a possible suicide attempt, when he was discovered unconscious in his cell with marks around his neck.
The Metropolitan Correctional Center (MCC), where Epstein was being held, did not immediately return The Hill's request Saturday for clarification about Epstein's suicide watch.