A prominent leader of a hard-line Islamist group that backed ousted Egyptian president Mohamed Morsi has died in jail in Cairo, the interior ministry said on Sunday. It said Essam Derbala, a senior leader in Gamaa Islamiya, died on Saturday after returning from a hearing at his trial.
Gamaa Islamiya blamed the prison authorities for his death.
Police had arrested the 58-year-old in May on charges of inciting violence and joining a pro-Morsi opposition alliance.
A medical check-up showed Derbala had a fever, low blood pressure and diabetes, the ministry statement said, adding that he had a history of diabetes and also previously suffered strokes.
"While being taken to the hospital he started bleeding from the nose, and suffered low blood pressure and breathlessness that led to his death," it said.
Gamaa Islamiya issued its own statement accusing the prison authorities of "deliberately killing Derbala by depriving him of his medicine over the past few months".
"We hold the political and security apparatus responsible for his death," it said.
Derbala was also an opponent of ex-president Hosni Mubarak who was forced out in 2011. He was jailed for 25 years during Mubarak's rule for his alleged involvement in violence in Upper Egypt when Mubarak's predecessor Anwar Sadat was assassinated in 1981.