VIDEO: The pro-Morsi crowd and the gunfire:

Using videos and eyewitness testimony, Patrick Kingsley of The Guardian has reconstructed the events in Cairo of July 8, when Egyptian security forces shot and killed about 50 supporters of deposed President Mohamed Morsi.

The protesters had gathered outside Republican Guards Headquarters, where Morsi has been under de facto house arrest since the coup on July 3. Violence broke out about 3:30 a.m., as the crowd prayed — Morsi suppporters claimed the security forces opened fire without provocation, while the military insists its troops were responding to an attack on them as armed men tried to get into the Headquarters.

Kingsley’s findings, supported by videos from EA’s coverage:

1. The security forces fired first, using tear gas and then ammunition, soon after Morsi supporters sounded a warning by banging together pieces of metal. Accounts claiming protesters shot first are suspect.

Video filmed at 3:26 a.m.

2. By 3:40 a.m., there were casualties among the Morsi supporters. The first body arrived in the field hospital at 3:45 a.m.

Aftermath of the initial attack:

Photojournalist Ahmed Assem is killed by an army sniper:

By 4:30 a.m., the hospital was stretched to capacity, with most medical supplies running out.

3. By 4 a.m., the first of more than 600 arrests were being carried out.

4. Clashes between security forces and protesters escalated by 4:30 a.m., with protesters fighting back with fireworks and petrol bombs. Footage shows at least three gunmen armed with single-shot firearms.

Video of a gunman among the protesters:

5. Fighting ended about 7 a.m.