RICHMOND, Calif. -- A 50-year-old grandmother watching her grandchildren was killed and a teenage girl injured by stray bullets after a gunman opened fire outside a Richmond apartment building Monday night.

Authorities identified the dead woman as Lisa Washington, who family members say was just watching the children and talking with neighbors when the bullet cut her down.

"I'm upset about it," Washington's daughter, Melissa Thomas, 14, told the San Francisco Chronicle. "It's dreadful that that this can happen to someone. You can't go around killing people's mamas and grandmas. That's ridiculous. It goes to show that the violence has increased."

Sgt. Bisa French said police received numerous calls reporting gunfire at about 10:05 p.m.

French said the victims do not appear to have been the intended targets of the shooting.

"It appears that the suspect or suspects were chasing another individual who was the target," French said.

Officers responded to the 100 block of South 20th Street and discovered Washington fatally shot and a teenage girl suffering non-life threatening injuries, French said.

A vehicle has not been connected to the crime, and police believe the suspects likely approached the scene in a residential neighborhood on foot, French said.

No additional suspect information was available this morning.

French said Washington and girl do not appear to be the intended victims of the shooting, and a preliminary investigation indicates that the incident was not gang-related.

Washington's death was Richmond's 19th homicide this year.