A volatile mix of “disparaging comments” and alcohol fueled a fight among party bus passengers in a south metro movie theater parking lot that left a young man shot dead, another hit by gunfire and others running for their lives, police said Sunday.

Police and state investigators were piecing together details from the chaotic scene that erupted about 1:30 a.m. Saturday outside the AMC Inver Grove 16 theaters just off Hwy. 52 and south of Interstate 494 in Inver Grove Heights, where the bus was letting off the 40 to 50 passengers after the rolling birthday party celebration, said Police Chief Paul Schnell.

Billy Ray Robles, 19, of St. Paul, was shot in the parking lot and then moved onto the bus before medical personnel took him to Regions Hospital, where he died, Schnell said. Robles considered himself an aspiring rapper and has released a video on YouTube under the name BillyThaKidd.

Authorities are trying to find specific suspects but have yet to make any arrests, Schnell said. Emergency dispatch audio as police swarmed the scene revealed that the gunman, believed to be 18 to 20 years old, fled on foot after shooting Robles in the chest.

Another man who was on the bus was punched in the face and taken to Regions, while a third person in connection with the mayhem was pulled over in a speeding vehicle about 5 miles to the north of the theater and found to be shot in the leg, police added. That victim, a 16-year-old boy, was also taken to Regions and later released.

Two groups of men among those on the bus were exchanging “disparaging comments about where they came from or what the represented,” the chief said. “There were overtures of gang stuff. We don’t know if it was directly gang-related.”

After the one man was “punched a number of times, others tried to intervene,” Schnell continued. “Then came more fighting and yelling. People came off the bus [and] shots began to ring out. Some people hit the ground, and some began to run.”

One responding officer was heard on dispatch audio saying that “there is zero perimeter” securing the scene several minutes after police had responded.

The group of mostly females boarded the bus in the theater parking lot between 10 and 11 p.m. Friday and made stops in Minneapolis and Hastings as part of a birthday party bus gift from a woman to her younger sister, Schnell said.

“We do know there were a number of people who were quite intoxicated,” said the chief, who added that the passengers ranged in age from 16 to their mid-20s. “Alcohol was certainly a factor.”

The wounded 16-year-old was stopped in a vehicle with “several girls” that had been speeding on northbound Hwy. 52 near Butler Avenue in West St. Paul shortly after the gunfire, Schnell said. Dispatch audio disclosed that the teen had a stun gun in his possession.

The passengers were mostly from St. Paul, West St. Paul and Inver Grove Heights, and of various ethnic backgrounds, the chief said.

“We’re still trying to track everyone down ... and sort out how this whole thing erupted,” he said. “We were getting varying levels of cooperation from the people we did secure at the scene.”

Anyone with information about this case is urged to contact police at 651-450-2525.