The university student killed last week during clashes with security forces was shot dead by protesting fellow students, the general prosecutor's office said on Monday.
Mohamed Reda, 19, was killed on Thursday after police clashed with students protesting at Cairo University against the harsh jail sentences handed to female supporters of ousted president Mohamed Morsi.
The pro-Morsi protesters blocked roads outside of the campus, disrupted traffic and verbally assaulted security forces, a statement said. After failing to heed warnings from the police, water cannons were used to disperse them.
The statement specified that during the protest, "some protesters – male and female – fired birdshot guns, injuring Reda, who fell dead, and other students."
A post-mortem examination showed that Reda had died from three pellets fired from a four-caliber gun. However, according to the statement, investigations have proved that the security forces guarding Cairo University do not possess such a weapon.
The general prosecutor's office noted that the findings were also in accordance with eyewitness accounts and a coroner's report.
Reda's death has sparked outrage amongst students, prompting thousands to protest across several universities in Cairo and elsewhere.
In a subsequent statement, the student union from Cairo University's Faculty of Engineering, the same faculty in which Reba had been studying, slammed the prosecution's report as "lying" and a "fabrication," and vowed not to give up the slain student's rights, raising the possibility of renewed protests.
Security forces fired teargas on Sunday to disperse hundreds of Islamist student protesters who had gathered in central Cairo's Tahrir Square to condemn the killing of their colleague.
Last week, students protested a court ruling which sentenced 14 Islamist female protesters to 11 years in jail for taking part in clashes during a pro-Morsi protest in the Mediterranean city of Alexandria. The ruling has provoked a public outcry and been condemned by rights groups.
Egypt has been rocked by violent tumult since the army's July ouster of Morsi, after millions protested against his troubled one-year rule.
More than 1,000 people have since been killed in street clashes that have largely pitted Islamists against both their political opponents and security forces.