A man fatally stabbed his girlfriend and her mother during an argument, then drove to a bridge and jumped to his death Thursday before a police officer could stop him, police said.

After the stabbing, police locked down a nearby elementary school, fearing the man may try to come for his 6-year-old son. Police took the boy off campus, police Lt. Ted Matthews said.

The man apparently never went to the school, Matthews said.

Additional reporting from MyFoxLA.com

The man was identified as Walter Garcia, 38, Los Angeles police Detective Pat Barron said. The women were identified as Damaris Quiles, 35, and her mother, Carmen Quiles, 73.

Earlier in the morning, Garcia had gone to a home in Tujunga, northeast of downtown Los Angeles, and confronted his girlfriend, Barron said. His girlfriend had a restraining order against him.

The woman's mother heard the argument and came outside to intervene. Garcia became angry, stabbed the girlfriend with a knife and then stabbed her mother, police said.

Her mother died at the scene and his girlfriend died later at a hospital, Barron said.

The man drove east to Pasadena, where he jumped from the Colorado Street Bridge, Matthews said.

A caller reported that a man had climbed over a fence along the bridge and was on the outside railing, said Pasadena police spokeswoman Janet Pope Givens.

"The officer got there within a minute. The subject jumped before the officer had time to negotiate with him," she said.

The 150-foot-high bridge, built in 1913, is a historic landmark known locally as "suicide bridge" because dozens of people jumped from it over the years. The bridge spans the Arroyo Seco south of the Rose Bowl.

Damaris Quiles' brother, Edwin, said his sister and Garcia had lived together for several years. Their relationship had been strained in the past, but he did not think his sister was at risk, he said.

"We knew something was going on, but we didn't think this would occur," Quiles said.

Elsewhere, a man shot and wounded his daughter and her mother before killing himself Thursday at a suburban home in eastern Los Angeles County, authorities said.

Paramedics found three people with head wounds after a 911 call summoned them to the home, authorities said. The man, 54, was dead at the scene, a sheriff's statement said.

A woman, 50, was hospitalized in critical condition and the man's daughter, 26, was in stable condition.