John Reeves, a Navy pilot and the roommate of fellow aviator David Reis, killed himself in a multi-murder suicide that claimed four lives on New Year's Day in Coronado, Calif., police report.

In a press conference with the San Diego County Sheriff's Department, investigators told The Associated Press that John Reeves, 25, killed himself with a gunshot to the head. The other three victims, identified as Navy pilot David Reis, 25; his sister Karen, 24; and Matthew Christopher Saturley, 31, have all been listed as homicide victims.

John Reeves and David Reis, both lieutenants junior grade, were roommates in the Coronado condo. Karen Reis worked at a San Deigo grocery store and served as a volleyball coach while she worked towards getting certified as an occupational therapist. No information has been released about the fourth victim, Matthew Saturley, except that he was from the Chula Vista area.

According to the official autopsy, David Reis died from a gunshot wound to the torso, his sister Karen from shots to the head and chest, and Saturley from multiple gunshot wounds.

Our condolences go out to the families, friends, fellow service members and Coronado community during this time of mourning, said Lt. Col. Robert Brodie, commanding officer of Marine Fighter Attack Training Squadron 101 at Miramar.

The investigation, including forensics and witness testimony, is ongoing, according to the L.A. Times, and is expected to take weeks. Investigators gave no motive for Reeves' multi-murder-suicide, but sources within the department had indicated jealousy might have been a factor.