U.N. rights experts say Egypt's ex-President Mohamed Morsi endured "brutal" prison conditions that contributed to his death in custody.
They also warn that thousands more prisoners are "at severe risk" from "gross violations" in Egyptian prisons.
Morsi, Egypt's first democratically elected president, was from the Islamist, now outlawed Muslim Brotherhood. He was ousted by the military in 2013, after protests. He'd been jailed for six years until his death in a Cairo court while on trial.
Friday's statement by the Office of the United Nations High Commissioner for Human Rights says the experts concluded that conditions Morsi endured "could amount to a state-sanctioned arbitrary killing."
They say he was in solitary confinement for 23 hours a day, was denied medical care, lost vision in one eye and suffered recurrent diabetic comas.