NEW YORK (AP) — Amid revelations about the circumstances around Jeffrey Epstein’s death, federal authorities have intensified parallel inquiries into what went wrong at the Manhattan jail where he was behind bars and who now may face charges for assisting or enabling him in what authorities say was his rampant sexual abuse of underage girls.

One of the new details provided by people familiar with the Metropolitan Correctional Center was that one of Epstein’s guards the night he died in his cell wasn’t a regular correctional officer.

Serene Gregg, president of the American Federation of Government Employees Local 3148, told The Washington Post that one of the guards was a fill-in who had been pressed into service because of staffing shortfalls.

In addition, Epstein was supposed to have been checked on by a guard about every 30 minutes. But investigators have learned those checks weren’t done for several hours before Epstein was found, according to one of the people familiar with the episode. That person was not authorized to discuss the matter publicly and spoke on condition of anonymity.

A second person familiar with operations at the jail said Epstein was found with a bedsheet around his neck. That person also wasn’t authorized to disclose information about the investigation and spoke on condition of anonymity.

Epstein, 66, was found Saturday morning in his cell at the MCC, a jail previously renowned for its ability to hold notorious prisoners under extremely tight security. At the time of his death, he was being held without bail and faced up to 45 years in prison on federal sex trafficking and conspiracy charges unsealed last month.

Attorney General William Barr at a police conference on Monday said that he was “frankly angry to learn of the MCC’s failure to adequately secure this prisoner.”

He added: “We will get to the bottom of what happened and there will be accountability.”

At the same time, Barr warned on Monday that any co-conspirator in the ongoing criminal probe “should not rest easy. … The victims deserve justice, and they will get it.”

In the days since Epstein’s death while awaiting charges that he sexually abused underage girls, a portrait has begun to emerge of Manhattan’s federal detention center as a chronically understaffed facility that possibly made a series of missteps in handling its most high-profile inmate.

Epstein had been placed on suicide watch after he was found in his cell a little over two weeks ago with bruises on his neck. But he had been taken off that watch at the end of July and returned to the jail’s special housing unit.

The manner in which Epstein killed himself has not been announced publicly by government officials. An autopsy was performed Sunday, but New York City Chief Medical Examiner Dr. Barbara Sampson said investigators were awaiting further information.

The Associated Press does not typically report on details of suicide, but has made an exception because Epstein’s cause of death is pertinent to the ongoing investigations.

In the criminal case, authorities are most likely turning their attention to the team of recruiters and employees who, according to police reports, knew about Epstein’s penchant for underage girls and lined up victims for him. The Associated Press reviewed hundreds of pages of police reports, FBI records and court documents that show Epstein relied on an entire staff of associates to arrange massages that led to sex acts.

If any Epstein assistants hoped to avoid charges by testifying against him, that expectation has been upended by his suicide.

“Those who had leverage as potential cooperators in the case now find themselves as the primary targets,” said Jacob S. Frenkel, a former federal prosecutor.

Associated Press writer Michael Biesecker contributed to this report.