Tehran — Leading academics in Iran wrote to President Hassan Rohani on Monday, demanding answers over the alleged "suicide" of a revered environmentalist in prison.

The family of Kavous Seyed Emami, 63, a renowned professor at Imam Sadegh University and founder of the Persian Wildlife Heritage Foundation, was told on Saturday that he had killed himself in prison two weeks after his arrest.

A judiciary official claimed on Sunday that he had confessed to crimes related to an espionage investigation, and seven other members of his wildlife NGO are still behind bars.

"The news of the death of Dr Kavous Seyed Emami has astounded and shocked the scientific community and the environmental activists of the country," wrote a group of four academic societies in an open letter to the president.

"In addition to being a well-known professor, a distinguished scientist and war veteran... he was a noble and ethical human being," the letter said.

"The news and rumors related to his arrest and death are not believable."

The letter was published by four leading academic associations related to political science, sociology, peace studies and cultural studies, which include professors from Iran's top universities.

Addressing Rohani, they wrote: "Our minimum expectation is that you take immediate and effective action to seriously investigate the case... and make the institutions involved in this painful loss accountable."

Asked about the case on Monday, judiciary spokesman Gholamhossein Mohseni Ejeie told the reformist ILNA news agency: "I have heard he committed suicide but I have so far no information on the details. This recent incident is under investigation."

Separately, the Environment Protection Organization denied rumors that its deputy head Kaveh Madani had been arrested.

A reformist lawmaker, Mahmoud Sadeghi, had stated via Twitter on Sunday that the EPO had told him Madani was arrested over the weekend.

A senior official at the EPO, who did not wish to be named, told AFP on Monday that this was incorrect and that Madani was at work.

A tweet was published on Madani's personal Twitter account early Monday for the first time in three days.

"Hopeful for narrow mindness to get wiped out. Hopeful for peace of mind for environmental activists. Hopeful for the removal of concern of those awaiting the return of loved ones," it read. — AFP