Eleven dead bodies with signs of torture were found near the Muslim Brotherhood's protest camps in Rabaa al-Adawiya Mosque in Nasr City and Nahda Square in Giza, an official security source said in a statement.
The security source added that 10 individuals have filed reports stating that they were subjected to torture inside the Brotherhood's sit-ins as they were accused of being "infiltrators".
He added that the ambiguity behind three corpses that were found in Giza earlier this month was cleared as they were identified, saying that their bodies also had torture marks.
The official said that the police arrested one suspect who has admitted to being involved in torturing to death those whom he and other protesters suspected of being "infiltrators" at their Nahda Square sit-in.
The interior ministry appealed to citizens who might have any information on such incidents to report them.
Loyalists to deposed Islamist President Mohamed Mursi have been holding sit-ins for nearly a month in Rabaa al-Adawiya and Nahda Square, demanding his reinstatement following his overthrow by the army that came in response to mass protests across Egypt.
