Attorney General William Barr on Monday blasted corrections officials and vowed to investigate the “serious irregularities” uncovered at the federal prison in Manhattan where accused sex trafficker Jeffrey Epstein was held and found dead Saturday morning. Barr's criticism came amid complaints about squalid, rat-infested cells and as union officials charge warnings about overworked employees at the understaffed facility went unheeded.

Barr vowed a comprehensive probe by the FBI and the Justice Department inspector general as the new and disturbing revelations emerged Monday from lawyers and others who say the failings at the Metropolitan Correctional Center in Lower Manhattan have been ignored for years.

Barr, speaking during a conference for the Fraternal Order of Police in New Orleans, also assured that the sex-trafficking case will continue against anyone who conspired with Epstein, and said victims will see justice in the end.

BARR 'APPALLED' BY JEFFREY EPSTEIN DEATH, SAYS QUESTIONS 'MUST BE ANSWERED'

“This sex trafficking case was very important to the Department of Justice, and to me, personally," Barr said. "It was important to the dedicated prosecutors at the Southern District of New York and to our FBI agents who investigated the case, and were preparing it for trial."

“Most importantly, this case was important to the victims who had the courage to come forward, and deserve the opportunity to confront the accused in the courtroom,” he continued. “Let me assure you this case will continue on against anyone who was complicit with Epstein. Any co-conspirators should not rest easy. The victims deserve justice, and they will get it.”

Epstein, who was accused of sex trafficking minors, was found unresponsive inside his cell at the Metropolitan Correctional Center in New York City around 6:30 a.m. on Saturday. Life-saving measures were initiated immediately by staff. He was then transported to New York-Presbyterian Lower Manhattan Hospital, where he was declared dead on arrival, officials said.

His death was described by officials as an apparent suicide, but investigations are underway into how the wealthy financier could have killed himself while in a high-security facility just two weeks after being placed on suicide watch.

“I was appalled, and indeed, the whole department was – and frankly, angry – to learn of MCC’s failure to adequately secure this prisoner,” Barr said Monday. “We are now learning of serious irregularities at this facility that are deeply concerning and demand a thorough investigation.”

He added: “The FBI and the Office of the Inspector General are doing just that. We will get to the bottom of what happened and there will be accountability.”

Barr's mention of "irregularities" refers to several emerging details surrounding Epstein's detention.

A source familiar with the matter told Fox News on Monday that Epstein's suicide watch had been lifted recently. Fox News also has learned that according to normal MCC operations, Epstein should have been checked on, physically, every 30 minutes, but apparently was not for “several hours” leading up to his death. A source also told Fox News that Epstein did not have a cellmate on the night of his death.

Epstein was initially put in a cell with Nicholas Tartaglione, a former policeman in New York who was charged in 2016 with the deaths of four men stemming from an alleged cocaine drug conspiracy.

Tartaglione's lawyer, Bruce Barket, told Fox News Monday that he has had several clients who have been locked up in New York City's notorious Riker's Island jail and MCC, and noted that many have said they "would rather be at Rikers."

"That gives you some idea how bad the place is," Barket said, going on to describe the poor conditions at MCC. "At the end of the day, the facility is run with a bad combination of laziness and cruelty and this is one of the results."

Barket said the conditions at MCC "border on inhumane." Barket said the ventilation systems in the facility are "decrepit," noting that some days the cells are boiling hot, while other days are bitterly cold. Barket said the air that circulates is so dirty that officers have even complained that it made them sick. He went on to note that there is black mold in the showers and cells, and that many units are infested with insects and rodents.

One morning, Barket said, Tartaglione woke up to discover that, while asleep, he'd rolled over on a rodent, smothering the pest.

Separately, Fox News spoke to a representative from the American Federation of Government Employees/Council of Prison Locals who decried the low staff levels at MCC, but also said the issue is a "system-wide crisis in our prison system."

EPSTEIN'S ALLEGED SEX TRAFFICKING VICTIM NAMES BILL RICHARDSON, GEORGE MITCHELL IN NEWLY RELEASED DOCUMENTS

Epstein’s death at MCC also came hours after more than 2,000 documents were unsealed by the U.S. Attorney’s Office for the Southern District of New York. The papers included affidavits and depositions of key witnesses in a lawsuit the now-33-year-old woman, Virginia Roberts Giuffre, filed against Epstein and his associate Ghislaine Maxwell in 2015. Giuffre accused the duo of keeping her as a “sex slave” in the early 2000s when she was underage.

In the documents, Giuffre claimed to have been forced to have sex with and provide erotic massages to powerful politicians, foreign leaders and businessmen. Giuffre alleged she was forced to have sex with former New Mexico Gov. Bill Richardson; Britain’s Prince Andrew; the late American scientist Marvin Minsky; hedge fund manager Glenn Dubin; “another prince;” “a large hotel chain owner;” Stephen Kauffman, and model scout Jean Luc Brunell.

Giuffre also revealed that she was “trafficked” to former Democratic Sen. George Mitchell, who represented Maine from 1980-95, served as Senate majority leader, and was later named special envoy to the Middle East by then-President Barack Obama.

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Mitchell, Richardson and Dubin denied the allegations in statements to Fox News on Friday. Prince Andrew has also vehemently denied the allegations.

Giuffre also has long claimed that Epstein forced her to have sex with Harvard law professor Alan Dershowitz. In the newly revealed documents, Giuffre, who was at the time labeled as “Jane Doe #3,” claimed that Epstein required her to have sexual relations with Dershowitz on numerous occasions while she was a minor. Giuffre claimed to have had the encounters in Florida, on private planes, in New York, New Mexico and in the U.S. Virgin Islands.

Dershowitz has emphatically denied the allegations.

Meanwhile, included in the hundreds of pages of documents were flight logs from Epstein’s private jet. Prominent individuals who had traveled on the jet, according to those records, included Bill Gates, who flew once; former President Bill Clinton and aide Doug Band, who flew four times; President Trump, who flew once in 1997 from Palm Beach to New York; Colombian President Andres Pastrana; Dershowitz; Hyatt Hotels Chairman Tom Pritzker; Brunel; and model and talent agent Naomi Campbell, among others.

Epstein had pleaded not guilty to sex trafficking and sex trafficking conspiracy last month in New York. Epstein, 66, was accused of having preyed on dozens of victims as young as 14.

Fox News' Jake Gibson, Robert Gearty, Tamara Gitt and Bryan Llenas and The Associated Press contributed to this report.