Police have admitted Elliot Rodger was "severely mentally disturbed" and his family had told officers they were concerned - but were opportunities missed to stop his killing spree?
Santa Barbara sheriff Bill Brown told reporters they had encountered Rodger three times - the most significant on April 30 when a family member asked police to check on him.
"(Police) found him to be polite and courteous. He downplayed the concerns for his welfare and the deputies cleared the call," said Sheriff Brown.
"They determined he did not meet the criteria for an involuntary mental health hold. He appeared timid and shy."
In his rambling online 'manifesto', Rodger describes his relief that his plans for murder had not been discovered.
"For a few horrible seconds I thought it was all over," writes the 22-year-old, who says his plans for a "Day of Retribution" began last summer when he claims he was attacked at a party.
In pictures posted on social networking websites, Rodger appeared to be a privileged young man who enjoyed the trappings of his Hollywood filmmaker father's success.
In reality, he was documenting his inner torment and making painstaking preparations for the killing spree that left six innocent people dead in knife and gun attacks.
Rodger described taking down his YouTube videos to head off suspicions over his mental health.
Police told reporters the killer said he was having social problems and would not be returning to school for the next year.
"The deputies discussed options available to him in terms of support offered", said Sheriff Brown, who added such call-outs were a routine part of the job.
The Rodgers' family lawyer, Alan Shifman, said Elliot had been diagnosed with Asperger's syndrome - a form of autism - at a young age.
"He was probably a victim, from my understanding, of bullying throughout his life," said Mr Shifman. "I am sure that played a role in the terrible consequences of last night.
