LAS CRUCES, N.M. (AP) — Police released video footage and 911 emergency calls Tuesday depicting chilling scenes of people running in panic as gunfire crackled in a New Mexico park where three people were killed and 15 others were wounded during an unauthorized car show.

One of the video recordings, taken by a bystander and shown by Las Cruces Police Chief Jeremy Story at a news conference, captured a blue Mustang doing donuts in a parking lot on Friday night just before gunfire erupts and people in a crowd flee in chaos.

The man recording the cellphone video is heard saying, “Oh my god, I just witnessed a murder!” before the video ends. The police chief credited the man for putting his phone away and helping the wounded.

Authorities said Friday night’s shooting at Young Park started after an altercation broke out between two groups at the gathering, which had drawn about 200 people. In court documents, prosecutors described it as one of the most horrific incidents to occur in Las Cruces, which is about 40 miles (70 kilometers) from the U.S.-Mexico border.

Story on Tuesday called it a massive and chaotic scene.

He showed police body camera footage of officers running through the parking lot and helping those with gunshot wounds — one tended to a man who was shot in his arm and leg while another wrapped a bandage around a woman who had been shot. She was crying; the officer told her to keep breathing and that she would be OK.

Some of the wounded were bystanders who were not involved in the dispute between the two groups. Authorities said the groups had past personal issues.

“This is not a traditional active shooter event where the motive or motivation is to kill and injure as many people as you can, as quickly as you can,” Story said. “Unfortunately, the results were the same.”

Four people are facing murder charges, including three teenagers. The police chief said more arrests and charges are possible, but he did not elaborate because the investigation is ongoing.

Las Cruces Mayor Eric Enriquez, also speaking at the news conference, said hearts are heavy with sorrow in his community for those family and friends affected by the tragic event.

“Let me be clear, this incident will not be tolerated in our community. We stand united against violence in all of its forms,” Enriquez said, adding that authorities will work to ensure those responsible will be held accountable.

Those facing first-degree murder charges are Tomas Rivas, 20, and three teenage males, including two 17-year-olds and a 15-year-old. The Associated Press typically does not name suspects younger than 18.

Investigators have collected evidence that includes the accounts of multiple witnesses who identified two of the shooters by name. They also said those two suspects allegedly dumped firearms at an apartment complex after the shooting. Officers had followed Rivas and one of the teenagers there and detained them after watching the teen toss a bag into a dumpster, they said.

Story said he believes all firearms used in the shooting have been recovered and that three of the guns were reported stolen.

The dozens of shell casings found at the park matched the caliber of the firearms that were found at the apartment complex, according to court documents.

Rivas made a brief court appearance Monday. The teens were scheduled to appear in children’s court Tuesday. Prosecutors are seeking to keep Rivas in custody as he awaits trial and they are seeking to prosecute the teens as adults.

At the time of the shooting, Rivas was prohibited from possessing a firearm because of a pending case in El Paso County, Texas, according to prosecutors. They said Rivas is facing charges there of evading arrest and smuggling of persons.

Rivas’ public defender has not returned messages from The Associated Press seeking comment. The state public defender’s office is also representing the teens but declined to comment on the allegations against them.

Andrew Madrid, 16, and Jason Gomez, 18, died at the scene. Dominick Estrada, 19, died later at a hospital. The wounded ranged in age from 16 to 36 and were treated at the park or taken to hospitals.