A lawyer of film director Peter Rodger says the family called police several weeks ago after being alarmed by YouTube videos posted by his son "regarding suicide and the killing of people".
The attorney said police had conducted an investigation and interviewed the man. Police said the man appeared to have trouble making friends but did not find a history of guns.
Police have not formally named the suspect, who died following the attack.
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Police are trying to find the driver of the car following the incident in Kingfisher Close, Brownhills.
An unnamed man died at the scene, while a woman was pronounced dead after being taken to St George's Hospital, Tooting, south-west London.
Eastern areas will see a few showers coming in on the northeasterly breeze