Hawzah News Agency (Buraydah, Saudi Arabia) - A dissident Saudi cleric has passed away in detention due to what reports suggest were health complications caused by “medical negligence.”

Sheikh Saleh Abdulaziz al-Dumairi died Saturday while being kept at Tarfiya prison in Saudi Arabia’s north-central city of Buraydah, human rights group Prisoners of Conscience (PoC), said on its Twitter page.

The independent non-governmental organization, which promotes human rights in Saudi Arabia, said Saudi authorities kept Dumairi in solitary confinement even as he was suffering from heart problems.

The dissident cleric had been detained on several occasions in the past over his political activism, and support for other anti-regime figures.

Dumairi’s death comes as a crackdown led by Crown Prince Mohammed bin Salman against pro-democracy campaigners, Muslim preachers and intellectuals continues in the Saudi Arabia.