The two, including the teenager, were arrested Saturday for mass shootings at a New Mexico car competition that killed three teenagers and injured 15 people.
Thomas Rivas, 20, and an unidentified 17-year-old boy were arrested and charged with three counts of undisclosed murder. Officers announced Sunday.
The Las Cruces Police Department is expected to see additional charges against the pair fall in the coming days.
Police on Sunday also revealed the identities of the three victims as Andrew Madrid, 16. Jason Gomez, 18; Dominic Estrada, 19, was killed when two fighting groups fired fire at Young Park on Friday.
Madrid and Gomez died at the scene. Estrada was rushed to a nearby hospital where he succumbed to his injuries, officers said.
Fifteen other people, ages 16-36, were injured in mass shootings. Nine were male, six were female, police officers were female, and most were treated in hospitals.
Police Chief Jeremy Story, Las Cruces Police Chief, said on Saturday that some were “fighting for their lives,” but police did not say the extent of the survivors' injuries.
The shooting erupted just after 10pm in a Young Park parking lot where around 200 people gathered for an illegal car competition.
An argument between the two groups with long-standing beef escalates to gunfires, rushing bystanders into frenzy and finding cover. Some of the injured were bystanders caught in a crossfire, the story said.
“I know there's some kind of malicious intention between these groups before last night. They had some issues before and escalated last night,” Story said.
Police have not explicitly said that Rivas and the teenage suspects are members of the fighting group. Similarly, it is not clear whether Madrid, Gomez and Estrada took part in the shooting or were on the sidelines.
“There were firearms throughout this event, some were used in the shooting, and people are willing to firearms through the time that leads to it based on the video they've been provided,” the story said Saturday.
So far, about 50 shell casings have been collected from the scene, all from handguns.
The majority of the shooting took place in the park, but several casings were found in the surrounding streets.
The investigation is ongoing and police continue to ask the public to provide video and other evidence from the shooting.
