A 28-year-old man shot and killed three members of a southern California family before turning the gun on himself, authorities said Friday.

The four bodies were found late Thursday inside a home in a residential area of Pomona, police lieutenant Michael Keltner said at a morning news conference.

The suspect lived at the home, and the crime appears to have stemmed from a domestic situation, Keltner said. A woman in her 50s and her 24-year-old daughter and 17-year-old son were killed in their respective bedrooms, he said.

The suspect was found at the foot of the younger woman's bed. Keltner said she may have been his girlfriend. There were no signs of a struggle.

Their names were withheld, pending notification of their relatives.

Officers went to the house after the man called relatives of the victims and said he was going to harm the family, police said.

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