CAIRO, June 26 (RAPSI) - Egyptian police have arrested eight extremists over the killing of four Shiites in a Cairo suburb, the country's Interior Ministry announced Tuesday. 

The massacre of the Shiites took place last Sunday in Zawyat Abu Musalam, a small village to the south of Cairo. Among those killed in the attack was the famous Egyptian Shia preacher Sheikh Hassan Shehata. A Sunni mob, led by Salafis, attacked the cleric's house, where some 20 Shiites were celebrating the wedding of one of the members of the community.

Video footage posted on social networking websites shows people wearing traditional Arab dress dragging people out of the house and beating them with batons.

Egyptian investigators are studying the footage together with witness testimony. The massacre of supporters of Egypt's second most popular branch of Islam is the first of its kind in the history of modern Egypt.

The attack was condemned by Al-Azhar, a respected Islamic university, stating that Islam, Egypt, and Egyptian society never accept killing on the basis of faith, sect, or belief. "This is an alien practice that is meant to disturb the stability of the nation at this critical moment and drag us into turmoil," the Al-Azhar statement reads.

However, a number of Salafi leaders refrained from condemning the atrocity and threatened other Shiites with a similar fate unless they stop spreading "heresy" and "insulting" the "companions of the Prophet."

Critics of President Mohammed Morsi are reportedly blaming him for the incident.