A sergeant in the U.S. Air Force killed his girlfriend and best friend before shooting himself to death in what authorities called an ambush-style attack, the Daily Mail reports.

Investigators believe that Michael Zamora, 30, shot Savannah McNealy, 22, and Tristan Kemp, 26, before killing himself with a gun on Thursday in a Fort Collins, Colorado, apartment complex.

Police have not yet released a motive for the 2 a.m. shooting but said it came after the gunman and three victims had socialized.

“Right now we don’t know what the motive was,” Fort Collins Police Chief Terry Jones told the Denver Post. “We’re not ruling out a love triangle.”

Kemp and McNealy were shot numerous times while Zamora died from a single, self-inflicted gunshot wound.

Jones has said the victims were dropped off by an Uber or Lyft service at the apartment just prior to the shooting.

Zamora also had been out socializing with the victims, but he did not ride back with them, the Daily Mail reports. McNealy was celebrating her 22nd birthday on the night of the shooting.

A third victim, a woman who has been hospitalized for unspecified injuries, is expected to survive.

Investigators found a handgun and two rifles registered to Zamora where the shooting occurred.

Zamora was a staff sergeant at an Air Force base in Wyoming, but he had been a resident of Fort Collins.

According to Tristan Kemp’s uncle, Thomas Perez, Zamora served in the Air Force with Kemp while the two were deployed to Afghanistan. They also had worked for the same company at one point.

Kemp had been living in Hawaii but the men made a trip Colorado so Zamora could see McNealy.

“I can say this much about my nephew: He was an American hero,” Perez said. “He proudly served the United States and the people. When he got out of the Air Force, he continued to serve as a civilian.”

McNealy was a student at Colorado State University studying liberal arts, art and art history. She also worked for the student publication CSU Life.

Hours after the shooting, pools of blood were visible on a sidewalk in the apartment complex. Investigators were focused on that area and a vehicle in a parking lot.

Neighbor Darren Rutz told The Rocky Mountain Collegian that he was awakened by what he thought was a woman’s cry for help and then a burst of gunfire.

“It seemed like quite a few gunshots to me,” Rutz said.

Another area resident, Matthew Litton, said he was in bed when multiple gunshots rang out.

“I could tell from the consistency of the firing that it wasn’t fireworks, it was gunshots,” Litton said. “I heard a girl yelling, ‘call 911!’ After that, I heard one last bang, and then it was quiet.”

Litton says he saw a picture from a friend that showed two bodies on a sidewalk with a gun in between them.

Anyone with information about the shooting is urged to call investigators at 970-221-6575.

[Feature image: Instagram]