Three of the four people found dead inside a Pomona home overnight Thursday were apparently shot to death before a 28-year-old man turned the gun on himself, police said.
Among the dead was a 52-year-old mother, her daughter, 25, and son, 17, according to Pomona police and neighbors, some of whom described hearing multiple gunshots shortly after 11 p.m.
The shooter thought to have carried out the murder-suicide was a 28-year-old man who was in a relationship with the daughter, Pomona police Lt. Mike Keltner said.
Neither the victims nor the suspected gunman was identified.
While there were no signs of struggle, investigators said two of the victims were awake when they were confronted, including the daughter, who was found next to the shooter, Keltner said. One of the victims was still in bed, he added.
"This could've happened within 30 seconds easily," Keltner said.
The man, police said, had called a relative saying he was going to harm the family, prompting a welfare check by officers, who discovered the bodies shortly after midnight.
Leonardo Piña, 38, lives down the street and described hearing at least four or five gunshots around 11 p.m.
He said that while the neighborhood was accustomed to violent crime, the apparent murder-suicide was a jolt to residents who described the family as being quiet but friendly.
"We're used to drug stuff and gang crimes, but not a murder-suicide," Piña said. "This is something different, it's horrible."
Investigators were still trying to determine the 28-year-old man's motive for the shooting, Keltner said.
Neighbors said he was the daughter's live-in boyfriend, but knew little about him. The family largely kept to themselves, they said, although it had made significant improvements over the years to what had been a rundown house.