Epstein, arrested in July 2019 on charges of trafficking underage girls for sex, was found hanged in his New York jail cell the following month while awaiting trial over abuses against under-age women.

His former associate Brunel, in his mid-70s, had been charged with the rape of minors and held in prison since December 2020. 

He was briefly freed in late 2021 but then re-incarcerated on a Paris court of appeal ruling.

A source close to the investigation told AFP Brunel had been found dead overnight Friday to Saturday in the Prison de la Sante. Paris prosecutors later confirmed he had died.

The source said he had been found hanged, but this was not confirmed by prosecutors.

Police are now investigating the cause of death, added the source, asking not to be named.

Brunel's death means his case is closed, unless other suspects are implicated in the same case in the future.

'Leaving behind secrets' 

Brunel had denied the charges. He was first detained in December 2020 at Paris Charles de Gaulle airport.

His lawyers, Mathias Chichportich, Marianne Abgrall and Christophe Ingrain, said his apparent suicide was "not guided by guilt but a profound sense of injustice".

"His tragedy is that of a 75-year-old man crushed by a media-judicial system," they said in a statement.

"Brunel had always maintained his innocence and had intensified his efforts to prove it."

Allegations from women who say they were abused in France in the Epstein case prompted French prosecutors to open their own investigation.

That probe focused on Brunel, who was accused in US court documents of rape and of procuring young girls for his friend.

Anne-Claire Le Jeune, lawyer for the plaintiffs, expressed "frustration and bitterness over not being able to obtain justice, just as for the victims of Epstein". 

"It took so much courage to be able to speak up, to be heard by the police and the investigating judges. It's quite terrible for the victims", she said.

She added that the victims had the feeling Brunel was "leaving behind a number of secrets".

Prince's settlement 

Brunel began his career as a model scout and in 1978 was involved in setting up the prestigious Karin Models agency. 

He then moved to the US where he cofounded the Miami-based agency MC2.

In US court documents, Virginia Giuffre, a key plaintiff against Epstein, accused him of using her as a "sex slave" and said she had been forced to have sex with well-known politicians and businessmen, including Brunel. 

She also alleged Brunel would bring girls as young as 12 to the US and pass them on to friends, including Epstein.

Giuffre on Saturday responded to news of Brunel's death on Twitter.

"The suicide of Jean-Luc Brunel, who abused me and countless girls and young women, ends another chapter," she wrote.

"I'm disappointed that I wasn't able to face him in a final trial to hold him accountable, but gratified that I was able to testify in person last year to keep him in prison."

Brunel's death comes days after Queen Elizabeth II's second son Prince Andrew settled the lawsuit brought by Giuffre, sparing him the public humiliation of a trial.

Giuffre has said she had sex with Andrew when she was 17 and a minor under US law, after meeting him through Epstein.

The prince, 61, has not been criminally charged and has denied the allegations.

In December, socialite Ghislaine Maxwell, a friend of Epstein and Prince Andrew, was convicted in the US of recruiting and grooming young girls to be sexually abused by Epstein.