An Irish lecturer in Paris was allegedly murdered by a Muslim student offended by a drawing of Mohammad.

John Dowling, 66, was stabbed 13 times in the throat and chest by his former student Ali R. a native of Pakistan, outside the Leonard de Vinci university. No other students saw such an image and police say there is not evidence of it, Voice of Europe reports.

Prosecutor Catherine Denis says Ali,37, held an “obsessive resentment” against the university since he was expelled in September 2017.

“He came to France two years ago to join the management school, but did not pass his first year,” Denis said. “Since then he had been returning to the college, and had become unwanted to the point that he was not allowed in any more.”

Ali R. confessed to the killing and told police he held a personal grudge against Dowling after failing his exams last year, the Daily Mail reports.

Irish Tricolour flag hangs from a tree in respect to #JohnDowling who was murdered by a Student in #Paris

— Hibernia (@mcairns75) December 7, 2018

He told police that the teacher had made fun of the Muslim religion during English classes at the university.

Ali, who had just renewed his residency permit to stay in France, told authorities, he killed Dowling because “He produced a drawing, which he showed off in class, insulting the prophet Mohammed.”

However, no other students remember such an incident.

Police have ruled out any links between Ali R. and jihadi groups.

Denis said, “We don’t have proof of radicalization, but rather a feeling that we’re dealing with someone who is very religious, very pious, very practicing.”

Dowling, who had taught English and international relations at the university for two decades, was due to retire at the end of this academic year.