Prominent Swiss Muslim theologian, Tariq Ramadan, has denied allegations of rape and sexual assault and has served notice of his intention to sue for slander, according to his lawyer Yassine Bouzrou.

French media outlets are reporting that Ramadan intends to file a complaint for “slanderous denunciation” on Monday with the public prosecutor of Rouen.

Henda Ayari, a French former Salafist turned secular liberal activist, filed a complaint on Friday against Ramadan at the Rouen public prosecutor’s office.

The complaint concerns “rape, sexual assault, wilful violence, harassment and intimidation.”

Ramadan, 55, is the grandson of the founder of the Muslim Brotherhood group in Egypt. He is a professor of contemporary Islamic studies at the University of Oxford in the United Kingdom.