A team of Egypt's Public Prosecution office on Saturday examined Mar Girgis Church to start a probe into an incident in which at least one was killed and 45 others wounded, the official MENA news agency reported.
Meanwhile, the public prosecutor is interrogating an extremist who fomented disturbances.
Some 5,000 Muslims, who were instigated by rumors that an anti- Islam play was screened in Mar Girgis Church, on Friday set off after Friday noon prayers from mosques in the Alexandria district and headed to the church in the same area to show their protest.
Police forces were obliged to use tear gas to disperse the demonstrators when some radical elements in the crowd began hurling stones at the church, police and passers-by and setting fire at commercial establishments in the area.
Fifty-nine protesters were detained in the wake of the riot and were transferred to office of the district attorney for questioning.
On Wednesday, Mohamed el-Sayyed Hassouna was arrested for injuring a nun and a lawyer while leaving the same church. He was also triggered by the alleged anti-Islam play.
However, a senior Coptic Church official denied claims that the play includes insults to Islam.
Source: Xinhua