LONGMONT, Colo. (KDVR) — Police reports shine a little light on what led up to a drive-by shooting at a Longmont park over the weekend that hospitalized a 15-year-old boy and killed 13-year-old Zay Rosales.

Longmont police officers were dispatched to Kensington Park at 1:49 p.m. Saturday, Aug. 20. Rosales was shot in the chest, unresponsive and not breathing when an ambulance arrived, according to the police affidavit.

A Longmont police officer applied a tourniquet to the second victim, who had been shot in the leg, the affidavit read.

Officers worked to track down a silver-colored vehicle, and witnesses described the driver leaning out toward the passenger window, pointing a gun and firing shots. A witness said there were no passengers in the suspect’s car.

Officers found roughly 10 empty shell casings on the street.

One witness told police there was a gang altercation at the Boulder County Fairgrounds involving “PBG” and “ESL” gang members. According to a question and answer segment from Longmont Police on local gangs featured in the Times-Call, the “East Side Latinos” and “Pretty Boy Gangsters” were two of the 13 gangs the police department identified in the mid-2000s.

According to the affidavit, a witness said “PBG members had been sending threats” through Instagram, targeting an individual, whose name was redacted, and his friends. One of the accounts sending threats was later identified as Yahir Solis, who was charged with first-degree murder and attempted first-degree murder in connection to the shooting.

It took police six minutes to find a vehicle that matched the description involved in the crime. Longmont Sgt. Michael Marquardt found a 2014 Ford Focus and “placed a stop on the vehicle.” The driver, 19-year-old Solis, had an active misdemeanor arrest warrant out of Boulder County for shoplifting.

Solis was detained. No witnesses could confirm whether Solis was the gunman since they didn’t get a good look at the suspect, according to the affidavit. Police walked around Solis’ Ford Focus without entering the car, and noticed “what appeared to be either a shell casing or a live round in the door sill area.”

Police conducted a gunshot residue test after arresting Solis on the active warrant.

After the car was impounded and taken to the Longmont Police evidence warehouse, officers searched the car and found “a backpack on the front passenger floorboard with a baggie with what appeared to be bullets inside.” Officers found the handgun wedged between the driver’s seat and the center console, according to the affidavit.

District Attorney Michael Dougherty stated, “In the immediate aftermath of this awful shooting, the Longmont Police Department responded very quickly and worked hard to determine what led to this tragic death. The work on this case will continue and, together with the Longmont Police Department, we will pursue justice for the victims and their loved ones. I join with the Longmont Police Department in calling for peace in our community. It is moments such as these when our community must come together; further violence is not the answer. We encourage witnesses to come forward.”