The family of Elliot Rodger, the 22-year-old who killed six people and then himself near the University of California, Santa Barbara Friday night, said they tried to intervene to stop their son from going on a murderous rampage. 

Rodger's mother said she got a call from her son's therapist Friday saying that he had emailed a manifesto about going on a shooting spree, according to the Detroit Free Press. 

She then went to her son's YouTube channel, and found a video in which he threatens to kill people. She alerted authorities, and went to find her ex-husband. 

But it was too late: by the time the authorities arrived at Isla Vista, he had killed six people, and then turned a gun on himself. 

"They're in deep, deep grief," family friend Simon Astaire said Sunday. "Their grief which is nearly unbearable to be close to is as much for the loss of their son as for the victims."

Rodger's mother had tried to intervene before. In April, she called one of her son's counselors after seeing disturbing videos that he posted on YouTube. The counselor called a mental health service then alerted the police. 

After deputies showed up to Rodger's apartment to check on his mental health, they determined that he didn't pose a threat. 

Police were not aware of his true mental state or his willingness to commit violence, as he did not have a violent history or previous institutionalizations. 

"Obviously, looking back on this, it's a very tragic situation and we certainly wish that we could turn the clock back and maybe change some things," said Sheriff Bill Brown. 

"At the time deputies interacted with him, he was able to convince them that he was OK," he said.

However, Rodger's family said that he was seeing therapists. 

In Rodger's email manifesto, he says he was able to convince the police that he did not have suicidal thoughts, and that he was glad the deputies did not search his apartment, as they would have discovered a number of weapons he used in the shooting spree. 

He said he posted many YouTube videos leading up to the attack. 

"On the week leading up to date I set for the Day of Retribution, I uploaded several videos onto YouTube in order to express my views and feelings to the world, though I don't plan on uploading my ultimate video until minutes before the attack, because on that video I will talk about exactly why I'm doing this," Rodger wrote.

He posted a final video Friday in which he sits in a black BMW and acts out scripted lines and planned laughter. 

Rodger describes his hatred for his roommates and the human race, and particularly maligns women who would not date him, and voices his hatred for the men they chose over him. 

He says that he would start the rampage by "silently killing as many people as I can around Isla Vista by luring them into my apartment through some form of trickery." 

He began a shooting rampage around 9:30 p.m. Friday, which lasted 10 minutes. He shot and killed three people at random, and injured 13 others with gunshots and his SUV. 

On Sunday, the three other victims in his rampage, who were found his his apartment, were identified as Cheng Yuan Hong, 20, George Chen, 19, and Weihan Wang, 20. Hong and Chen were Rodger's roommates. 

Officials found three semi-automatic handguns in the vehicle, purchased legally, with 400 unused rounds.