The Muslim Brotherhood on Monday accused the Egyptian government of “assassinating” former President Mohamed Morsi by detaining him in inhumane conditions and denying him health care.

67-year-old Morsi fainted in court and died on Monday after delivering what a judicial source described as an “animated” speech to the judge for about 25 minutes. Speaking from within a glass cage in the courtroom, Morsi threatened to reveal “many secrets” if he remained in prison.

Morsi was elected president in 2012 after the fall of longtime dictator Hosni Mubarak, but was then himself ousted by current President Abdel Fattah el-Sisi.

Morsi was criticized for attempting to turn Egypt into a hardline Islamist state in accordance with the philosophy of the Muslim Brotherhood, leading to huge protests against his rule. The Muslim Brotherhood was banned after Sisi took power in the summer of 2013. Sisi has since won two presidential elections but has in turn been accused of abusing his authority to crack down on dissent.

Morsi was convicted on charges of using violence to disrupt protests against his government when he was in power and sentenced to 20 years in prison and also faced a death sentence for a mass prison break in 2011 during the uprising against Mubarak.

Egyptian Attorney General Nabil Sadek released a statement soon after Morsi’s death saying “no recent injuries were found on the body of the deceased.” A full inquest into the cause of his death was promised.