FORT WORTH, Texas — Four of the nine people killed in a melee between rival biker gangs outside a Texas restaurant were struck by the same caliber of rifle fired by Waco police, according to evidence obtained by The Associated Press that provides the most insight yet into whether authorities were responsible for any of the deaths and injuries.

The latest trove of potential grand jury evidence reviewed by the AP depicts a chaotic, bloody scene in which police swarmed into the shootout between rival biker gangs on May 17 outside the Twin Peaks restaurant that left about 20 wounded and nearly 200 people arrested.

Hours of audio and footage and hundreds of documents including ballistics reports show four of the dead and at least one of the wounded were struck with bullets from .223-caliber rifles – the only type of weapon fired by police that day.

Two of the four dead had wounds from only that kind of rifle; the other two were shot by other kinds of guns as well. The ballistics reports show that the rest of the people killed were shot by a variety of other guns.

It was not clear whether any bikers had similar guns to the police that day. Among the hundreds of weapons authorities recovered from the scene were 12 long guns, which could include rifles.

Waco Police Chief Brent Stroman had said in June that officers shot a total of 12 rounds using the semi-automatic setting on their .223-caliber rifles. The AP has previously reported that evidence showed some of those shots struck bikers, but didn’t indicate whether they were fatal.

Police and the district attorney’s office declined to comment on the latest evidence, but have defended the officers’ use of force, claiming that bikers had also opened fire on police.