French police have searched the Paris apartment of convicted sex offender Jeffrey Epstein and the offices of a model agency belonging to his alleged associate Jean-Luc Brunel, himself accused of rape and of procuring minors for his friend.

The Paris prosecutor’s office confirmed that investigators had carried out searches at Brunel’s Karin Models in the 8th arrondissement of Paris and at Epstein’s luxury 800 sq metre apartment on the exclusive Avenue Foch near the Arc de Triomphe.

Police sources told local media the search of the late US financier’s residence, part of a French probe into allegations that he and others had for years trafficked underage girls for sex, began at 3pm on Monday and continued until 4am on Tuesday.

Epstein’s Franco-Brazilian butler told the Franceinfo news site that the apartment contained a specially built massage room to which “a great many women” had come. He added that he was not able to judge whether any of them were minors.

Facebook Twitter Pinterest Jeffrey Epstein was found hanged in his cell in a New York prison in August, while awaiting trial on sex-trafficking charges. Photograph: AP

Epstein was arrested on 6 July in New Jersey after returning in his private jet from Paris. He pleaded not guilty to charges of sex trafficking involving dozens of girls as young as 14, but on 10 August was found hanged in his cell.

The disgraced financier’s ownership of an apartment in Paris, and allegations from women who say they were abused in France, last month prompted French authorities to open their own criminal investigation into half a dozen possible charges of rape and sex abuse, including of minors.

The probe focuses on potential crimes committed against French victims in France and abroad, and on suspects who are French citizens, the Paris prosecutor has said. Police have appealed for victims and witnesses to come forward.

The whereabouts of Brunel, who founded Karin Models in 1978, has been unclear since August. He has been named as a close friend of Epstein’s who often flew on his plane and visited him in jail in Florida when he was serving a previous 13-month sentence for procuring a girl under 18 for prostitution.

The Frenchman, who now lives mainly in the US and has denied all wrongdoing, has been accused in court documents of rape and procuring minors for Epstein, who at one time counted Bill Clinton, Donald Trump and Prince Andrew among his friends.

Jean-Luc Brunel, seen here in Australia’s Next Top Model, in 2008, was a close friend of Epstein and is accused in US court documents of rape - which he denies. Photograph: Fox8

Three women have already given evidence to investigators in France. They include a former Dutch model, Thysia Huisman, who has told the Guardian how she was invited to Paris in 1991 with the promise that Brunel would make her famous, but subsequently drugged and raped by the model scout in his flat.

In the US, Virginia Roberts Giuffre has alleged Epstein used her as a “sex slave”, forcing her to sleep with politicians and businessmen including Brunel. She accused the Frenchman of bringing girls as young as 12 to the US and passing them on to his friends.

Brunel, who claims to have launched the careers of top models Monica Bellucci, Sharon Stone, Christy Turlington, Jerry Hall and Milla Jovovich, was accused of rape by several models in a CBS documentary as early as 1988.

In 2015 he issued a statement vehemently denying any involvement, “directly or indirectly”, in any of Epstein’s crimes. “I strongly deny having committed any illicit act or any wrongdoing in the course of my work as a scouter or model agencies manager,” he said then.