Concern about Islamic radicalism in Egypt surfaced with the stabbing death of a university student while his girlfriend looked on.
The couple was sitting in a quiet park when three suspected Islamic radicals approached, telling them they should not be together in public.
The Islamists told Ahmed Hussein Eid, 20, and his girlfriend to leave immediately and go their separate ways because they were not married.
According to security officials, who spoke on condition of anonymity because they are not authorized to speak with the media, an argument ensued and one of the men pulled a knife and stabbed Eid in his upper left thigh. He later died of his wounds in the hospital.
Eid's killing is stoking fear that vigilante groups are seeking to strictly enforce Islamic teaching.
Security officials say there's no evidence to link the three to any of the main Islamic groups in Egypt.