He also was required to register as a sex offender and pay restitution to the underage girls he abused.
The Federal Bureau of Investigation (FBI) and the US Justice Department are both investigating the "apparent suicide", federal authorities said.
Epstein had been jailed since early July, when he pleaded not guilty to charges by NY federal prosecutors after an indictment accused him of sex trafficking dozens of underage girls, some as young as 14 years old.
USA prosecutors said Epstein used his wealth and power to sexually abuse dozens of young girls for years at his homes, paying them hundreds of dollars in cash for each encounter and hundreds more if they brought in more victims.
Epstein's death came just hours after the release of 2000 pages of court documents relating to Giuffre's case and detailed names and alleged incidents of abuse.
Sigrid McCawley, an attorney representing one of the alleged victims of Jeffery Epstein, speaks to reporters in front of a courthouse in New York, Thursday, July 18. Epstein was being held in federal Bureau of Prisons custody after a federal judge denied him bail. In October, Boston gangster James "Whitey" Bulger was killed in a federal prison in West Virginia where had just been transferred.
In the wake of Epstein's suicide, union president Eric Young of the American Federation of Government Employees Council of Prison Locals said a Trump administration hiring freeze at the Bureau of Prisons has led to thousands of vacancies and created "dangerous conditions" for prison workers and inmates.
"I was appalled, and indeed the whole department was, and frankly angry to learn of the MCC's failure to adequately secure this prisoner", Barr said at a police conference in New Orleans. He said that, in 2002 and 2003, Clinton took four trips on Epstein's plane with multiple stops and that staff and his Secret Service detail travelled on every leg.
Epstein's arrest drew national attention, particularly focusing on a deal that allowed Epstein to plead guilty in 2008 to soliciting a minor for prostitution in Florida and avoid more serious federal charges.
The Miami Herald and other media outlets petitioned the court to have the lawsuit documents unsealed.
He was denied bail last month in a NY court because he was deemed a flight risk.
The investigation into the sex trafficking and conspiracy charges against the 66-year-old will continue despite his death, the federal attorney in charge of the probe also said on Saturday.
The young women were paid hundreds of dollars in cash to massage him, perform sexual acts and to recruit other girls, prosecutors alleged.
The non-prosecution deal that had prohibited Florida authorities from going after co-conspirators of Jeffrey Epstein should be voided now that the pedophile is dead, a lawyer for two of his accusers said Monday.
His friends over the years have included Donald Trump, Britain's Prince Andrew and former Harvard law professor Alan Dershowitz.
Trump has acknowledged knowing Epstein but said he "had a falling out with him a long time ago".
The case became an unexpected hot-button issue in Israel's election campaign after Epstein's longstanding ties to former prime minister Ehud Barak were revealed.
Donald Trump and his girlfriend (and future wife), former model Melania Knauss, financier Jeffrey Epstein, and British socialite Ghislaine Maxwell pose together at the Mar-a-Lago club, Palm Beach, Florida, February 12, 2000. "Simple as that", she said.