Sheikh Namazie’s cousin, Abdelhameed al-Faris, a cleric with the ruling Al Qaeda-linked Jabhat al-Nusra, told the London-based al-Hayat newspaper: “I can neither affirm nor deny if he died under their leadership. I can only say that they did not allow his wife and family to see him.”

He is now feared to have been killed while in police custody in November when authorities raided a cafe he was thought to have frequented in Damascus’s Bustan al-Qasr neighbourhood, where he was thought to have been working.

“He was a very kind person and a good person,” said Mohammed Yusef, a business associate. “I can no longer speak about his situation. He had his responsibilities to maintain the security of his community.”

The death of Hadi was not the first of its kind in the Syrian capital. In 2013, Mohammad Khouri, a religious scholar, also died in custody from malnutrition. A report in a Turkish daily newspaper, Hurriyet, on Monday quoted a police source as saying that a “criminal case was being opened” against Hadi’s relatives.

The Syrian Observatory for Human Rights said earlier this month it had documented 4,724 fatalities and 1,965 wounded in the country since July. More than 11,000 people have been abducted, it added, with nearly 1,850 deaths.