A senior leader of the Muslim Brotherhood died Thursday in an Egyptian prison where he was serving multiple sentences including on terror-related charges, his lawyer said.
Essam al-Erian, 66, was arrested in 2013 following the ouster of former president Mohamed Morsi on the back of mass protests against his brief rule.
"The authorities notified me of his death, and I informed his family to arrange for receiving his body (for burial)," lawyer Abdelmoneim Abdelmaqsood told AFP.
"It was a natural death," he added.
Egyptian media reported that Erian died of a heart attack following an argument with a fellow inmate.
Erian was the vice president of the Brotherhood's political wing, the now-dissolved Freedom and Justice party.
He was sentenced in multiple cases on charges including incitement to violence, murder and espionage.
Authorities placed Erian on their terror blacklist, a designation that has allowed them to freeze his assets.
According to AFP, Morsi himself died in custody in June 2019, after falling ill during a court hearing.