CAIRO – The highest-level inquiry into the deaths of nearly 900 protesters in Egypt’s uprising has concluded that police were behind nearly all the killings and used snipers on rooftops overlooking Cairo’s Tahrir Square to shoot into the crowd.

The report, parts of which were obtained by The Associated Press, is the most authoritative and sweeping account of the killings and determines that the deadly force used could only have been authorized by Hosni Mubarak’s security chief, with the ousted president’s full knowledge.

The report of the fact-finding commission, created by Islamist President Mohammed Morsi, could weigh heavily in the upcoming retrial of Mubarak, as well as his security chief, former Interior Minister Habib el-Adly, and six top police commanders. It is likely also to fuel calls for reforming the powerful security forces and lead to prosecutions of members of the police force.

The findings were leaked at a sensitive time for the country’s police. Still hated by most Egyptians, the force is in upheaval, with segments of police on strike and its chief, Interior Minister Mohammed Ibrahim, pleading not to drag it into politics. The force is also facing a challenge from Islamist groups threatening to set up “popular committees” to fill what they call a security vacuum created by the police strike.

Part of the force also is protesting what some officers see as an attempt by Morsi’s Muslim Brotherhood to control the force. The Brotherhood denies the charge.

The Interior Ministry, which controls the police, has repeatedly rejected charges that it bore responsibility for the killings in Cairo and other cities during the 18-day uprising that began on Jan. 25, 2011, and ended with Mubarak stepping down. In contrast, the pro-democracy activists behind the uprising have long maintained that police were to blame.

Mubarak and el-Adly, the second most powerful figure after the ousted leader, were convicted and sentenced to life in jail in June 2012 for failing to stop the killings, but the two have successfully appealed their convictions. The six top police commanders put on trial with Mubarak and el-Adly — including the head of security in Cairo and the commander of the riot police — were acquitted of charges related to the killings. The prosecution appealed that verdict and a new trial of the eight will start next month.