State Security Investigations Service

The State Security Investigations Service (Egyptian Arabic: مباحث أمن الدولة Mabahith Amn El Dawla) was the highest national internal security authority in Egypt. Estimated to employ 100,000 personnel, the SSI was the main security and intelligence apparatus of Egypt's Ministry of Interior. The SSI focused on monitoring underground networks of radical Islamists and probably planted agents in those organizations and had the role of controlling opposition groups, both armed groups and those engaged in peaceful opposition to the government. It has been described as "detested" and "widely hated".

Following the 2011 Egyptian revolution, the head of the SSI was arrested under suspicion of ordering the killings of demonstrators. On March 15, 2011, the Ministry of the Interior announced the dissolution of the agency. The service was replaced by (or renamed) the Egyptian Homeland Security after the 2013 Egyptian coup d'état.