Tariq Ramadan is said to have seduced four of his teenage pupils in shocking new allegations against the prominent Islamic scholar.
According to The Tribune de Geneve newspaper, the incidents took place in the 1980s and 1990s when he was teaching in his hometown of Geneva.
Four of his former students have come forward with this new information. One of them claimed that he tried unsuccessfully to seduce her when she was just 14 years old. He allegedly targeted three others, who were aged between 15 and 18 years old at the time, according to the newspaper's report.
It is the latest in a string of damning allegations about Mr Ramadan, who is a professor at Oxford University and the grandson of the founder of the Muslim Brotherhood in Egypt. Three women have accused him of rape or sexual assault in the past two weeks, providing graphic details in interviews and on social media. After the first accusation, Mr Ramadan issued a strong denial and filed counter-charges for libel.
The Tribune de Geneve said that four Swiss women, all non-Muslim, had agreed to testify about their former teacher's alleged behaviour towards them when they were just teenagers.
They described how they felt Mr Ramadan, who worked as the professor of French and Philosophy at the Cycle of Coudriers and then at the College de Saussure in Switzerland, exercised a strong psychological influence on them.
One, known as Sandra, was 15 when Mr Ramadan made advances towards her. She said he told her: "I feel close to you. You are mature. You are special. I am surrounded by many people but I feel lonely." She started spending time with him outside of school, and "two or three times we had intimate relationships. At the back of his car". She added: "He said it was our secret."
Another, Lea, said she was 14 years old when the teacher approached her during a trip. "He put my hand on my mouth telling me he knew I was thinking about him in the evening before falling asleep. Which was wrong. It was manipulation. He said he thought of me but he was married."
In her case, she says nothing physical happened. She described him as a "crooked, intimidating man who used perverse relational ploys and abused the trust of his students. There was such an impression on us."
A third woman, known as Agathe, was 18 and described being "captivated by the speech of this charismatic teacher". She said Mr Ramadan invited her for a coffee outside of school, "and then I had sex with him. He was married and a father. This happened three times, especially in his car. It was consented but very violent. I had bruises all over my body."
Agathe says the scholar threatened her and demanded she tell no one about the encounters. "It was an abuse of power, pure and simple."
The fourth woman, Claire, was 17 when the pair started a relationship and 18 when they first had intercourse. "I was fascinated, under his control. He took me, threw me, established a relationship of dependence."
None of these incidents was made public before now, with one of the women expressing feelings of "disgust" and "shame" which made her stay quiet.
Several former officials contacted by the Tribune de Geneve said they had heard rumours of Mr Ramadan's predatory behaviour, but denied actual knowledge of the acts.
"If the facts are true, we are deeply shocked," Pierre-Antoine Preti, head of communications at the Department of Education, told the newspaper.
The latest revelations suggest that Mr Ramadan may have been abusing women, including underage girls, long before the recent cases in France. The Paris authorities have opened an investigation after two women accused him of rape and a third accused him of sexual assault.
Last Saturday, Mr Ramadan wrote on his Facebook page: "These accusations are simply false, and betray all the ideals I have long strived for and believed in."
Supporters of Mr Ramadan are describing the accusations against him part of a Zionist plot to destroy his name.
But other former friends have come forward in recent days to disparage him.
Stephane Lathion, a Swiss specialist in Islam who spent years accompanying Mr Ramadan on his trips across Europe, told the Tribune de Geneve that he had heard various rumours and suspicions about his former close associate's behaviour over the years.
He shared his opinion with the paper, saying: "I'm not surprised to see testimonials coming from everywhere. Not only are the reported facts shocking, but they also reveal the discrepancy between his attitude and his discourse on a moralising Islam, which advocates sexual relations in the exclusive context of marriage."
He continued: "Tariq Ramadan is a predator who has abused his power as a teacher, preacher and intellectual to seduce women and girls, who have suffered."