A man has died from his injuries after being tortured by Egyptian police for three days, officials have said.
A protest against torture by police in the Egyptian capital
The officials - who refused to give their names - told foreign news agencies that Ahmed Saber Saad had been held on suspicion of drug possession.
But state prosecutors ordered his release, saying there was insufficient evidence against him.
The officials say that, instead, police tortured Saad for three days, before dumping him on the street in Giza.
He died a day later.
The Egyptian Prosecutor General Abdel Meguid Mahmoud has ordered an inquiry into the reports.
The case follows the sentencing on Monday of two police officers to three years in prison for sexually assaulting a man with a stick at a police station in Cairo.
Human rights groups say that torture is endemic in Egypt because suspects are held incommunicado for long periods and police interrogations take place without counsel.
The Egyptian authorities reject this and insist that cases of torture are investigated and prosecutions sought.