The mayor of Europe’s swinging capital is being held by police over accusations he spent taxpayers’ money on a “ventriloquist” fortune teller who “bewitched” him into thinking she had contacted his dead father.

The French Mediterranean town of Agde is notorious for its wild sex parties, which every year attract tens of thousands of partner-swapping couples from across the continent.

It is now in the national spotlight for the scandal involving Sophia Martinez’s “witch-like” powers of persuasion over Gilles d’Ettore, the mayor and a former officer with both the police and secret service.

Both are in custody while under investigation. Martinez faces charges of embezzlement. Ettore, mayor of Agde since 2001 and a former conservative MP for the area, has been accused of corruption over allegations he spent vast amounts of taxpayers’ money on the fortune teller.

Martinez, 44, had a reputation for being able to speak to the dead, with a long list of clients who wished to contact deceased relatives and access her “powers” as a “medium, hypnotherapist and healer”.

“I am a specialist in the cleansing of energy for people and places,” her Facebook page says.

Among the charges against her is tax fraud. Police found large sums of cash at her home.

It is claimed that when the mayor, 55, asked her to put him in touch with his deceased father, she was able to mimic the dead man’s voice with uncanny accuracy.

Ettore also received regular anonymous calls from someone claiming to be Archangel Michael, the patron saint of Agde, who spoke in a “raucous voice from beyond the grave” and told him to “protect Sophia and her loved ones”.

The mayor was so infatuated with Martinez that he considered her to be his daughter. He even walked her down the aisle last year at her lavish third wedding – said to have cost €80,000 ($141,000) – a bill footed by Ettore.

To pay her, Ettore allegedly enlisted the help of municipal employees and companies with links to the town hall, via a system of false invoices.

Nothing was too good for Martinez: she was treated to a new kitchen and veranda, trips to Polynesia and Thailand, and school fees for two of her six children, who were regularly driven there by the mayor’s chauffeur, according to the claims. It is also alleged that he gave council jobs to her husband and five family members.

After a complaint from Ettore’s ex-wife, who claimed he had been “bewitched” into embezzling council funds, police set up wiretaps and were amazed by her ventriloquist skills. At their request, she agreed to demonstrate these during her interrogation, which was filmed.

From beyond the grave

Prosecutor Raphaël Balland said: “Her strategy consisted of modifying her voice, including with members of her family and close friends.

“By using this male-sounding, hoarse voice, she succeeded in making them think they were talking with a supernatural being from the beyond.”

An officer told Midi Libre, the local newspaper: “When you watched this woman and heard that man’s voice resounding, you couldn’t imagine that it was coming out of her body. It’s astonishing.”

When the footage was shown to Ettore, “he couldn’t believe it,” said Jean-Marc Darrigade, his lawyer. “We had to show him this video for him to realise that he had been duped”, he told Le Parisien.

“He found himself involved with a perfectly malevolent character. This is the first case of misappropriation of funds that does not result in enrichment, but in personal impoverishment.”

But Luc Abratkiewicz, Martinez’s lawyer, said that while she has admitted betraying his confidence, “it’s not a case of manipulation because she has owned up to what she did and other clients including doctors and architects said she had mystical powers”.

One former customer, who claimed to have witnessed such powers, said objects moved inexplicably in her home during visits and Martinez was able to provide details about her life, such as where she had scattered her best friend’s ashes.

Rival politicians have expressed astonishment at the case.

Thierry Nadal, leader of the Agde council opposition, said: “This has stunned the whole population. It’s a really sad affair that is damaging our town, especially with this bizarre stuff with the clairvoyant.”.

Fabienne Varesano, a local politician from Marine Le Pen’s National Rally party, has called on the mayor to resign. “He has made a mockery out of our town,” she said.

Darrigade denied his client used council funds to pay for his séance, arguing that “the investigation has not yet formally proven this”.