Police arrested a man late Monday after two women and a 4-year-old girl were found dead and two other children wounded in a shooting at two Baldwin Park houses, authorities said.

Someone called 911 at about 7:30 p.m. to report the gunshot victims, said Andrea Hawkins, a Los Angeles County Fire Department supervising dispatcher.

When Baldwin Park police arrived, Los Angeles Sheriff's Lt. Daniel Rosenberg said, "they found a male Hispanic adult standing in the street. He was subsequently detained and found to be armed with a handgun."

Upon initial search, officers found a grisly scene.

"They found five gunshot victims," Rosenberg said.

"We believe the suspect who was detained got into some type of argument with his mother, shot and killed her, then went next door on some type of a shooting rampage and shot his neighbors."

Wounded were a 14-year-old boy and a 9-year-old girl. Both were taken to a hospital in critical condition, Rosenberg said.

The sheriff's department is investigating.

Television station KCAL reported that the man taken into custody has a history of mental illness.

Police with automatic rifles patrolled the working class neighborhood 18 miles east of downtown Los Angeles shortly after the shooting.

The area soon was blocked off by yellow crime scene tape. Police cruisers stood by as the bodies of the victims and the weapon used in the killings remained at the scene.