Two guards at a federal prison in Manhattan have been indicted in connection with the investigation into accused sex trafficker Jeffrey Epstein, a senior law enforcement official said.

Michael Thomas and Tova Noel, who were on duty the night before Epstein was found dead by suicide Aug. 10, have been indicted by a grand jury with six counts tied to falsifying prison records.

Thomas and Noel pleaded not guilty and and will be released on a $100,000 bond.

The allegations are that Thomas and Noel sat at their desk, browsed the internet, and moved around a common area of the federal Metropolitan Correctional Center, but never conducted any rounds that night.

The indictment says that from approximately 10:30 p.m. Aug. 9 until approximately 6:30 the next morning, when Epstein was found dead, the two never checked on him or any other inmate in the jail's special housing unit.

Epstein was in the cell closest to the common area, which meant the guards were approximately 15 feet away, the indictment says.

"Noel used the computer periodically throughout the night, including to search the internet for furniture sales," the indictment says. Thomas allegedly used the computer briefly at three different points during the night to search for motorcycle sales and sports news.

For a period of approximately two hours, "Noel and Thomas sat at their desk without moving and appeared to have been asleep," the indictment says.

The guards did not discover Epstein in his cell unresponsive until about 6:30 a.m. when they went into the unit to deliver breakfast. Minutes later, around 6:33 a.m., an alarm was activated and a supervisor arrived, almost immediately.

According to the indictment, Noel told the supervisor that "Epstein hung himself" and said that she and Thomas never completed the 3 a.m. or 5 a.m. rounds.

Thomas then stated, "We messed up," and added, "I messed up, she's not to blame, we didn't do any rounds."

The two are charged with falsely signing internal documents saying they did the checks and counts at 12 a.m., 3 a.m., 5 a.m., and that they did rounds at 30-minute intervals.

U.S. Attorney Geoffrey Berman said the two guards "had a duty to ensure the safety and security of federal inmates in their care at the Metropolitan Correctional Center. Instead, they repeatedly failed to conduct mandated checks on inmates, and lied on official forms to hide their dereliction.”

Kathleen Hawk Sawyer, director of the Federal Bureau of Prisons, said in a statement," Any allegations of misconduct are taken very seriously by the agency and will be responded to appropriately."

A lawyer for Thomas, Montell Figgins, said both guards are being “scapegoated,” The Associated Press reported.

“We feel this a rush to judgment by the U.S. attorney’s office,” Figgins said. “They’re going after the low man on the totem pole here.”

Prosecutors had wanted the guards to admit they falsified the prison records as part of a plea offer that they rejected, according to people familiar with the matter, the AP reported.

Epstein was arrested July 6 at an airport in Teterboro, New Jersey, as he returned from Paris on a private jet. He was charged with one count of sex trafficking conspiracy and one count of sex trafficking and faced up to 45 years in prison if found guilty.

He pleaded not guilty and was denied bail.

The indictment in his case alleged that he sought minors, some as young as 14, from at least 2002 through 2005 and paid them hundreds of dollars in cash for sex at either his Manhattan townhouse or his estate in Palm Beach, Florida.

Epstein pleaded guilty in 2008 to procuring a person younger than 18 for prostitution and felony solicitation of prostitution. He served a 13-month sentence in a Florida county jail and was granted a federal nonprosecution agreement.

Epstein, 66, was found dead in his downtown Manhattan federal jail cell Aug. 10 as a result of suicide.

Jeffrey Epstein appears in court in West Palm Beach, Florida, in 2008. Uma Sanghvi / Palm Beach Post via Reuters file

He was not on suicide watch at the time of his death despite a possible attempt weeks earlier, multiple people familiar with the investigation told NBC News.

U.S. Attorney General William Barr, who ordered the reassignment of Metropolitan Correctional Center's warden and the leave of the two guards following the financier’s death, has pledged a thorough investigation.

"We will get to the bottom of what happened, and there will be accountability," Barr said earlier this year.

Following Epstein’s death, federal prosecutors shifted their focus to possible charges against anyone who assisted or enabled Epstein in his alleged sex crimes. Agents searched his private island home off the coast of St. Thomas in the Caribbean in their quest for evidence, and Barr had a message for any potential accomplices.

"Let me assure you that this case will continue on against anyone who was complicit," Barr said at a law enforcement conference in New Orleans. "The victims deserve justice, and they will get it."