(Reuters) - A Navy airman behind a January murder-suicide in California came home from a New Year's celebration and lay in wait for a man and a woman he had partied with, shooting them before killing a fellow Navy lieutenant, police said on Wednesday.
The motive for the killings by Navy Lieutenant John Reeves, 25, remained unclear, the San Diego County Sheriff's Department said in a statement as they concluded their investigation.
Police had found within days of the New Year's Day slayings that Reeves was responsible for killing the three people. The latest findings said ballistics tests conclusively showed him to be the sole gunman.
Reeves and Navy Lieutenant David Reis, 25, had been pilots in training at a local air station and shared a condominium in the Southern California resort island of Coronado.
The two men and Reis' 24-year-old sister, Karen, returned to the condo from a San Diego nightclub in the early morning hours of New Year's Day, bringing home a man named Matthew Saturley, 31, whom they met at the club, police said.
Reeves entered first and armed himself with two firearms, a rifle and a pistol, and went to the third floor where he "lay in wait," the police statement said. Saturley and Karen Reis entered the condo after Reeves and went up to the third floor, where Reeves shot both of them with his M1 rifle, police said.
David Reis, in response to hearing his sister scream, then ran inside and made it to the base of the stairway to the third floor, where Reeves shot him with a handgun, police said. Reeves then shot himself in the head with the same gun.
"The investigation did not confirm a clear motive for the murders," the police statement said.
Ballistics tests concluded that Reeves fired the only two guns in the condo that were used in the shooting.
Saturley had been getting his master's degree in finance, local television station NBC San Diego reported earlier this year.
(Reporting by Alex Dobuzinskis; Editing by Cynthia Johnston and Eric Beech)