Bureau of Prisons faces more scrutiny after the death of Jeffrey Epstein

The death of accused sex trafficker Jeffrey Epstein is just the latest in a string of incidents that have plagued the Federal Bureau of Prisons in the last year.

Last October, mobster Whitey Bulger was stabbed to death within hours of his arrival at the U.S. Penitentiary at Hazelton in West Virginia. Bulger's death could have been prevented if the Hazelton penitentiary was properly staffed, a source told ABC News.

In January, the Metropolitan Detention Center in Brooklyn, New York, experienced a power outage for a week that was dangerous for both staff and inmates, prompting protests and calls from Congress to fix the situation.

"We are now learning of serious irregularities at this facility that are deeply concerning and demand a thorough investigation," Attorney General William Barr said on Monday. "We will get to the bottom of it and there will be accountability."

Epstein, a convicted sex offender, was found unresponsive in his cell around 6:30 a.m. on Saturday, the Bureau of Prisons said. He was transported while in cardiac arrest at 6:39 a.m. to New York Downtown Hospital, where he was pronounced dead, according to sources.

His death came less than three weeks after he was found unresponsive in his cell at the federal prison in Lower Manhattan, with marks on his neck that appeared to be self-inflicted, sources told ABC News. He was placed on suicide watch following the July 23 incident but had been removed at the time of his death.

Two sources familiar with prison conditions at the Metropolitan Correctional Center told ABC News that staffing there is "deplorable" and it was "only a matter of time" before staff and inmates would get hurt. One source familiar with MCC conditions said more than 30 staff positions are still vacant.

Some have said the hiring freeze at the Department of Justice, which has since been lifted, and the non-competitive salaries have affected staffing at these prisons.

The two guards that were at the Special Housing Unit where Epstein was housed were both working overtime. One officer was working a mandatory overtime shift. The other officer was working his fifth overtime shift of the week.

The BOP is one of several federal agencies operating under leadership of an acting director.

The facility has played host to some of the most high-profile inmates in the country, like former Trump campaign chairman Paul Manafort and Joaquín "El Chapo" Guzmán.

Jail protocols requiring routine checks on the well-being of MCC inmates like Epstein appear to have not been followed in the hours before the millionaire was found hanging in his cell, sources told ABC News.

Epstein should have been checked on by a correctional officer every 30 minutes, according to Bureau of Prison protocols. But sources told ABC News that protocol was not followed prior to Epstein’s death.

In recent weeks, the correctional officers' union has complained of understaffing. Those gripes are now part of the investigation into whether the 30-minute checks were happening.