London: The gunman who killed four people in a shooting spree in California, before police shot him dead, acted alone, US authorities have said.
According to the Daily Star, the violence began when the gunman, dressed in black and an ammunition belt, opened fire on a house where two bodies were found.
Two officials briefed on the investigation said those two victims were the gunman`s father and brother.
Police said earlier that seven people were killed, including the gunman but later confirmed that a total of five people were killed.
Police eventually shot the gunman dead in the library at Santa Monica College.
According to the report, police said he opened fire on a city bus, a police car and other vehicles, and bystanders and pedestrians.
The gunman continued to shoot at people in the library, Police Chief Jacqueline Seabrooks said, but apparently did not hit anybody there as dozens ran for the exits.
Meanwhile, investigators have released a man who had been detained as a person of interest.
Sergeant Richard Lewis, a Santa Monica police spokesman, told a news conference that the man was questioned and released and was not a suspect, the report added.