As people attempted to slowly advance to the aid site from the Al-Alam roundabout, more than a dozen witnesses interviewed by CNN described the IDF opening volleys of intense fire on the crowd starting as early as 3:30 a.m.

Robert Maher, a professor of electrical and computer engineering at Montana State University, who specializes in forensic audio analysis, examined the footage for CNN and said that the bursts of gunfire were at a rate of 15 and 16 shots per second (or 900 and 960 per minute), fired from a distance of about a quarter of a mile (450 meters).

Trevor Ball, a former US Army senior explosive ordnance disposal team member, said the rate of fire was consistent with the FN MAG, a heavily-used machine gun in the Israeli military’s arsenal. The FN MAG is commonly equipped on the IDF’s Merkava tanks, which several eyewitnesses said they saw open fire on the crowds.

Doctors working at Nasser Hospital shared photos with CNN of the bullets retrieved from patients injured and killed in the attack, which weapons experts say appear to match the type of ammunition used in the Israeli military’s machine guns. “This bullet is consistent with the NATO standard 7.62mm M80, which would be fired by IDF 7.62x51mm weapons, including the Negev 7.62 and FN MAG,” Ball said of one of the images.