Navy pilot David Reis and his sister Karen have been identified as two of the four people found dead on New Year's Day in what may be a murder-suicide.

Investigators have confirmed that David Reis, 25, was stationed at Marine Corps Air Station Miramar and lived in the three-story condo in Coronado, Calif. with two roommates, also believed to be in the military. Karen Reis, 24, lived nearby.

Investigators are still looking into the killings. They have not released the names of the two other men murdered in the condo, but ABC reports that David's roommate, John Reeves, 25, was the third victim. The fourth victim has been identified as a 31-year-old male from Chula Vista.

'I knew these guys were pilots.'

Don Hubbard, a neighbor and retired Navy commander, was the first to hear gunfire. When he woke up to the sound of shots, he thought the sounds must be coming from New Year's celebrations and went back to sleep.

Two hours later, Hubbard got a phone call, and heard SWAT teams swarming the area. He looked outside, and saw a Navy pilot lying in the condo's doorway, dead from multiple gunshot wounds.

I knew these guys were pilots because I was one and we'd talk about airplanes, Hubbard said.

The other three victims were found inside by police.

'There's so much love in this family.'

This kind of thing doesn't happen to people like her [Karen] and David, said Rebecca Bailey, who played volleyball with Karen at the University of California, San Diego.

Coronado is home to Naval Air Station North Island, and is a haven for retired veterans. Murders are rare (there was one homicide on record in 2010), and the affluent resort was known for its famous Hotel del Coronado and Navy presence, not for violence.

Their family is the family everybody wants to be a part of, Baily told The Daily News. There's so much love in their family.

Tom Reis, David and Karen's father, is still reeling from the loss. David Reis held a mechanical engineering degree from University of New Mexico and had just taken his first run in a fighter jet. His sister Karen graduated from UC San Diego in 2009 and was coaching volleyball.

He just had his first F/A-18 flight, Reis said of David. Oh man, he loved it.

'They all seemed to think it was a murder-suicide.'

The San Diego County sheriff's department has declined to say whether or not the killing of David and Karen Reis and the two other victims was a murder-suicide.

After a robot inspection of the California condo, however, San Diego County Sheriff Lt. Larry Nesbit said there were no outstanding suspects, and would not comment or whether a weapon was found or gunfire was exchanged.

Hubbard, meanwhile, says he spoke to police about the possibility of a murder-suicide, and claims they confirmed his suspicions.

I was very concerned because here we had a killing in my backyard, Hubbard said. I asked them and they all seemed to think that it was a murder-suicide.

'How could this have happened?'

According to ABC News, the Coronado Police Department, Naval Criminal Investigative Services, the sheriff's Homicide Detail and sheriff's Crime Lab are all participating in the investigation. No more information has been released.

We don't know the circumstances, Tom Reis said. We don't know what happened. We only know that they're no longer with us.

Don Hubbard remains shaken by his grisly discovery.

Even now, you say, how could this have happened? Hubbard asked. What the hell is going on here?