POMONA, Calif. >> A man who shot to death his girlfriend and two of her relatives before turning the gun on himself warned his own brother of the plan only minutes before the attack, police said Friday.

There was no time to prevent the tragedy after the 28-year-old man made the call late Thursday, and it appeared the gunman quickly mowed down the victims in bedrooms, police said.

“Basically, he went from room to room and killed everyone,” Lt. Mike Keltner told the San Bernardino County Sun (http://bit.ly/1izn038 ).

Officers called to the single-story home found the bodies of the gunman, two women and a teenage boy. The suspect was found at the foot of the younger woman’s bed and there were no signs of a struggle.

However, investigators believe at least two victims, including the younger woman, were awake when they were confronted and one victim was still in bed, Keltner told the Los Angeles Times (http://bit.ly/QoxTJS ).

“This could’ve happened within 30 seconds easily,” Keltner said of the attacks.

The Los Angeles County coroner’s office had not released the names of the dead Friday evening.

However, the family’s sole surviving member, April Mejia, said they included her sister, Mariana Padilla, 25; 17-year-old brother, Juan Padilla, and their mother, Manuela Padilla, 52.

The gunman was her sister’s live-in boyfriend but he was unemployed, wasn’t going to school, and their mother considered him a deadbeat and for months had tried to force him out of the home. “I know my mom wanted him out,” Mejia said. “She got fed up, asked him to leave.”

Mejia also told the Sun that her sister once mentioned that she wanted to leave her boyfriend.

However, “I wouldn’t think he would do anything like this,” she said.

Mariana Padilla was a pastry chef who would travel to restaurants to train employees, said a neighbor, Mary Luna.

She had promised to bake a cake for Luna for Mother’s Day, she told the Sun.

Leonardo Pina, 38, lives down the street and described hearing gunshots around 11 p.m. Thursday. He said that while the neighborhood is 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,” Pina told the Times. “This is something different. It’s horrible.”

Pomona is a city of about 150,000 people 30 miles east of downtown Los Angeles.