The UN human rights office called Tuesday for an "independent inquiry" into former Egyptian president Mohamed Morsi's death while in state custody.
"Any sudden death in custody must be followed by a prompt, impartial, thorough and transparent investigation carried out by an independent body to clarify the cause of death," said Rupert Colville, spokesman for the UN High Commissioner for Human Rights.
Morsi, Egypt's first democratically elected president in 2012 after the Arab Spring uprisings, was overthrown in 2013 after a brief, turbulent term in power.
He died Monday after collapsing during a trial hearing in a Cairo court.
"Concerns have been raised regarding the conditions of Mr. Morsi's detention, including access to adequate medical care, as well as sufficient access to his lawyers and family, during his nearly six years in custody," Colville said.
He noted that Morsi "also appears to have been held in prolonged solitary confinement," and said the investigation must "encompass all aspects of the authorities' treatment of Mr. Morsi to examine whether the conditions of his detention had an impact on his death."