In the days after Mr. Epstein’s body was discovered, conspiracy theories abounded. But the new details have begun to answer some of the questions about how such a high-profile prisoner, who had previously been on suicide watch, could have possibly gone unsupervised for several hours.

The jail workers fell asleep.

Two staff members at the high-security jail — the Metropolitan Correctional Center — who were supposed to check on Mr. Epstein every 30 minutes fell asleep, law enforcement and jail officials told The Times .

Mr. Epstein’s cell went unchecked for about three hours, the officials said. Both staff members in the special housing unit where Mr. Epstein, 66, was held falsely logged that they had inspected his cell as required.

The two workers, whose names have not been released, were placed on administrative leave as the F.B.I., the Bureau of Prisons and the Justice Department continued their investigations regarding Mr. Epstein’s death.

The jail’s warden, Lamine N’Diaye, was reassigned to a Bureau of Prisons office in Philadelphia.

One of the staff members watching Mr. Epstein was not a guard.