A neighbor dialed 911 late Saturday to report shots fired. Two minutes later, the teen told police that his father had shot him and his brother at their condo complex in Yorba Linda, a bedroom community about 40 miles southeast of Los Angeles.
Police found five people, including three children, dead of gunshot wounds. The teen's mother was discovered on the doorstep, said Lt. Jack Conklin of the Brea Police Department, which was investigating.
Inside the home, police found the bodies of two girls in a bedroom; they had apparently been asleep in their beds. The body of a boy was discovered in another bedroom, along with the body of a man with a shotgun beneath him. Authorities are still figuring out a motive but believe the father was the gunman.
Judging by the number of shell casings found at the scene, investigators concluded that each victim was shot once, Conklin said.
The victims were identified as Orland Cho, 41; Maricel Cho, 39; Nicole Cho, 9; Kathleen Cho, 8; and Christopher Cho, 5. Authorities believe that the couple were married and that the teen was the woman's son from a previous relationship.
The teen, identified as Ian Mercado, was shot in the lower torso and underwent surgery at a hospital. He was expected to survive, but police can't interview him until Monday at the earliest because he remained sedated.
"At this point, he's the only surviving eyewitness," Conklin said Sunday.
The shooting rampage stunned police and residents of Yorba Linda, home to the Nixon Library. Conklin said the region has a low crime rate, with a homicide every few years.
"It's a very, very safe community," Conklin said. "This is very unusual."
The teen gave police a brief statement at the scene, recounting what he told the 911 dispatcher. It appeared the boy was unaware that his mother and sisters had also been shot, Conklin said.
On Sunday, coroner's officials removed the bodies while police searched the condo for evidence. Autopsies were planned for Monday.
Neighbor Reggie Straughter told the Orange County Register that he was watching television when he heard a loud sound. He ran outside and saw what he believed was a flash.
"They were very private people," the 40-year-old Straughter said.