Four dead and two hurt in LA shooting spree

A gunman has shot dead four people and injured two others across three Los Angeles suburbs before police arrested the man after a 12-hour manhunt.

Gerry Dean Zaragoza, 26, a suspect in a 12-hour rempage in Los Angeles' San Fernando Valley, being wheeled to an ambulance. Source: AAP

Four people have been shot dead and two injured in a shooting spree that spread across three Los Angeles suburbs.

The shootings touched off a 12-hour manhunt before police tackled and arrested an armed suspect.

A Los Angeles police spokesman identified the suspect as Gerry Zaragoza, 26, and said he was held on pending murder charges in the shooting deaths of his father and brother, and the wounding of his mother with a gunshot.

Police at the scene of the crime. Source: AAP

The shooting spree started at an apartment the suspect shared with his parents at about 2am on Thursday in LA's Canoga Park, police said.

Police said the suspect also allegedly shot and killed a woman he knew at a gas station in North Hollywood about 45 minutes later, but did not characterise their relationship.

Some media referred to her as a former girlfriend, others as an acquaintance.

At the same time, he allegedly shot and wounded a gas station clerk. The man was shot five times and was in critical condition, the Los Angeles Times and other media reported.

Later, at about 7.45am, police said Zaragoza allegedly shot a gardener he tried to rob at an ATM machine. And at about 1pm he allegedly shot and killed a man on a bus in the Van Nuys neighbourhood, police said.

Media reports say he did not know the man on the bus and that the shooting appeared to be random.

The Los Angeles Times reported that Zaragoza was arrested in Canoga Park after being tackled by plainclothes officers about 2.30pm. Police used a taser to subdue him.

An LAPD spokesman had no information on any bond set for Zaragoza, but said he remained in police custody early Friday.

It was unclear if he had an attorney.