On Monday, Marlene Schiappa, France's gender equality minister, had demanded an investigation into Epstein's affairs in France.
Attorney General William Barr said he was "appalled" by the news.
The suspicion in Epstein's death was hanging, said a city official not authorized to speak on the record. She is accused of recruiting teenage girls for Epstein and his associates.
Epstein was placed on suicide watch following the incident, but was taken off 11 days before his death. An autopsy was performed Sunday, but the city's chief medical examiner said investigators were awaiting further information. A private pathologist observed the examination, as well.
Before his downfall, Epstein had previously counted many prominent rich and powerful people, including Presidents Bill Clinton and Donald Trump, as friends.
Little St James, which Epstein bought in 1998, was seen swarming with Federal Bureau of Investigation, who were searching his island investigating the supposed sex trafficking ring that he was part of.
Inmates on suicide watch are subjected to 24 hours per day of "direct, continuous observation", according to U.S. Bureau of Prisons policy.
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In 2017, William, Kate and Prince Harry participated in a training session for runners taking part in the London Marathon. The event was held off the Isle of Wight and was brought forward a day due to the weather forecast.
Epstein was put under such observation after being taken off suicide watch at the MCC in late July, the person said.
Officials said in the Department of Justice statement that emergency responders tried to revive Epstein but he was pronounced dead soon after arriving at a nearby hospital.
The 66-year-old Epstein was being held without bail, awaiting trial on federal sex trafficking and conspiracy charges that could have brought 45 years in prison. "It's too early to say what I think should happen, but if this did occur as we believe that it did, some staff are going to have some hard questions to answer".
That agreement also gave immunity to potential co-conspirators of Epstein.
Democratic presidential candidates handed Trump a verbal smackdown for promoting theories about the death of the disgraced financier.
Corrections officers had not checked on Epstein for "several" hours before he was found around 6:30 a.m., a person familiar with the matter said, just one in a series of missteps in the hours leading up to his death.
Ms Giuffre, who now lives in Queensland, said she was angry that he would not face the courts after their years of struggle to be heard.
"Let me assure you that case will continue on against anyone who was complicit with Epstein", Barr said in remarks to a law enforcement group in New Orleans on Monday.
A French NGO defending children rights, Innocence Endangered, said France is concerned since several French citizen appear in the USA case and some alleged victims are French, in a letter addressed to Paris prosecutors published Monday by French magazine L'Obs.