The octogenarian detainee and former parliamentarian Ragab Mohamed Abu Zeid Zair died after his health deteriorated in his prison cell, the CFJ said.
Zair was a member of the parliamentary bloc of Muslim Brotherhood deputies from the Shebin al-Kom constituency in Menoufia governorate.
He was among thousands of then-army chief Abdel Fattah el-Sisi's opponents who were detained in 2013 following his coup against Mohamed Morsi, the country's first democratically elected president.
Zair was first detained in December 2013 and held in al-Qanater men's prison, and then again in October 2021, when he was held in Wadi al-Natroun prison complex, where he died.
Zair's family in February requested his release on medical grounds due to the deterioration of his health.
He was suffering a range of medical issues, including diabetes, bronchitis, an enlarged prostate, a weak heart muscle, as well as atrophy of the nerves of the hand. He also underwent a heart stent operation during his imprisonment. (ILKHA)