Californian serial killer Alexander Hernandez in custody

Bill McSweeney, Los Angeles County Sheriff's Department Chief Detective, left, with Los Angeles Police Department Deputy Chief Kirk Albanese, speak to the media in Los Angeles (AP)

A man accused of going on a terrifying killing spree in southern California, shooting seven people over a period of five days and leaving four of them dead, is in custody and is expected to be arraigned later today on charges that will include capital murder.

Police said the suspect, identified as 34-year-old Alexander Hernandez of the Sylmar district in the north of Los Angeles, had been taken into custody late Sunday after attempting to barricade himself in his home. He was being held on $1m bail and also faced charges of animal cruelty for shooting three dogs also.

Seized during the arrest was a pistol-grip shotgun that police believed was used by Mr Hernandez. He “is and was a serial killer” said chief of detectives Bill McSweeney.

The shootings began on 20 August when the suspect allegedly fired at a couple in a car on an interstate exit ramp. Investigators have seen no connections between those he targeted and believe he was picking them at random. Of those who died, three were shot during Sunday, hours before he was taken into custody.

Saying that Mr Hernandez appeared to have been acting on his own with no accomplices, the police sought to reassure the public that any danger had passed. Chief McSweeney also indicated that police departments in California had already began searching for anything that might connect Mr Hernandez to any unsolved murders going back several years, particularly with an eye to his weapon and the gold SUV he was driving.

So far Mr Hernandez has been charged with only one count of capital murder in the death of 48-year-old Gildardo Morales, who died after being fired upon driving to work on 21 August in his pick-up truck. The three dogs were all shot on 20 August and only one survived.