Prosecutors on Wednesday ordered the detention of Shia leader Mohamed al-Doreiny in Giza, after he was arrested Tuesday for alleged possession of illegal firearms.
Security forces had on Tuesday arrested Doreiny for keeping firearms hidden in his home in the Giza neighborhood of Haram.
Doreiny will be detained for 4 days pending investigations into charges.
The family of the arrested Shia leader told Al-Masry Al-Youm that Doreiny filed several reports with public prosecutors and other security bodies claiming that Salafi groups had threatened to assault his family.
When the police did not respond, Doreiny said he felt compelled to purchase weapons to protect his family.
The arrest of Doreiny comes just days after 4 Shias were killed in a Giza village when hundreds of residents attacked and tortured them for performing Shia rituals.
Some villagers were quoted as saying they were "proud" of what they had done, claiming the 4 Shias – including prominent local leader, Hassan Shehata – had been overheard insulting the Prophet Mohamed's companions and wives.
Shia activists have accused the police of negligence, saying they have failed to intervene despite being in the area.
The incident was condemned locally and internationally as all-out sectarian mob violence.
Prosecutors in South Giza detained 8 suspects on Tuesday, charging them with murder, premeditated murder, threatening public security and the illegal possession of arms.
Edited translation from Al-Masry Al-Youm