DUBAI, United Arab Emirates (AP) — An Iranian-Canadian university professor detained in Tehran has died in custody, activists and a family member said Sunday, marking the latest suspicious death of a detainee in Iran after a crackdown on dissent following nationwide protests.

They identified the professor as Kavous Seyed-Emami, a 63-year-old professor of sociology at Imam Sadeq University in Tehran and the managing director of the Persian Heritage Wildlife Foundation. His son and the New York-based Center for Human Rights in Iran say that authorities told Seyed-Emami's family that he committed suicide in custody, something they described as suspicious following other detainee deaths.

Iranian state media and officials did not immediately report Seyed-Emami's death on Sunday, as the country held nationwide rallies marking the 39th anniversary of the country's 1979 Islamic Revolution.

However, Tehran prosecutor Abbas Jafari Dolatabadi said Saturday that authorities had arrested several unidentified people on suspicion of spying.

"Tehran's prosecutor said those individuals, in the context of implementing scientific and environmental projects, sought to collect information ... on the country's strategic areas," a report by the state-run IRNA news agency said, without elaborating.

The professor's son, musician Ramin Seyed-Emami who performs under the stage name King Raam, also wrote on Instagram that his father had died following his arrest on Jan. 24.

"They say he committed suicide. I still can't believe this," he wrote.

Global Affairs Canada, the country's Foreign Ministry, said it was aware of reports of Seyed-Emami's death.

Iran entered the New Year with nationwide protests sweeping across 75 cities and towns. The demonstrations initially focused on Iran's poor economy despite its nuclear deal with world powers, but quickly spiraled into chants directly challenging Supreme Leader Ayatollah Ali Khamenei and its theocratic government.

Authorities arrested nearly 5,000 people in the crackdown that followed, according to Alireza Rahimi, an Iranian lawmaker. At least 21 people were killed in clashes surrounding the demonstrations.

Activists say they have concerns about Iran's prisons and jails being overcrowded and dangerous, pointing to allegations of torture, abuse and deaths that followed the mass arrests during Iran's 2009 Green Movement protests. Since the most-recent protests, activists have said they also remain concerned by reported suicides within Iran's prison system.

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