Two prison guards who were on duty on the night of disgraced financier Jeffrey Epstein's death have been charged with falsifying records.
They are accused of failing to check in on him every 30 minutes and fabricating log entries to show they had.
Both appeared in court on Tuesday and pleaded not guilty.
Epstein, a convicted sex offender, hanged himself in jail in August while awaiting trial on federal sex-trafficking charges.
He had pleaded not guilty to sexually abusing dozens of girls, some as young as 14.
The 66-year-old was previously jailed in Florida in 2008 for procuring a minor for prostitution.
The charges against the two guards are the first to arise from a criminal inquiry into his death.
What are the two guards accused of?
They were supposed to check on Epstein every 30 minutes on the night of his death. He had been taken off suicide watch after a previous suspected attempt to take his own life and was alone in his cell at the Metropolitan Correctional Center in New York.
But attorney Geoffrey Berman said the two guards had "repeatedly failed to conduct mandated checks on inmates, and lied on official forms to hide their dereliction".
The guards were named in a statement by the Southern District of New York Attorney's Office on Tuesday as correctional officers Tova Noel and Michael Thomas, aged 31 and 41 respectively.
For "substantial portions" of their shifts, they "sat at their desk, browsed the internet, and moved around the common area", the statement said. They then signed "false certifications" showing that they had conducted counts of inmates.
Both guards have been charged with "making false records and conspiring to make false records and to defraud the United States".
"We allege these officers falsified records to create the appearance they were following... protocols. The security risks created by this type of behaviour are immense," FBI assistant director William Sweeney said in the statement.
Surveillance footage showed that no other people had entered the area where Epstein was held that evening, the statement added.
Both guards appeared in court on Tuesday and pleaded not guilty. Bail was set at $100,000 (£77,000) each, US media reports.
Both guards were previously reported to have been working overtime shifts on the night of Epstein's death.
US Attorney General William Barr ordered their suspension in August after the FBI opened an investigation.
Federal prosecutors later offered the guards a plea bargain but they turned it down, according to the Associated Press news agency.
Who was Jeffrey Epstein and what was he charged with?
New York-born Epstein worked as a teacher before moving into finance. Prior to the criminal cases against him, he was best known for his wealth and high-profile connections.
He was often seen socialising with the rich and powerful, including US President Donald Trump, former President Bill Clinton and the UK's Prince Andrew.
Epstein was accused of paying girls under the age of 18 to perform sex acts at his Manhattan and Florida mansions between 2002 and 2005. He was arrested on 6 July.
He avoided similar charges in a controversial deal in 2008, pleading guilty to a lesser charge of soliciting and procuring a minor for prostitution.