GOLETA, Calif. (AP) -- Sheriff's deputies who showed up at Elliot Rodger's doorstep last month to check on his mental health hadn't seen online videos in which he threatens suicide and violence even though those recordings were what prompted his parents to call authorities. By the time law enforcement did see the videos, it was too late: The well-mannered if shy young man that deputies concluded after their visit posed no risk had gone on a deadly rampage on Friday. The sheriff's office "was not aware of any videos until after the shooting rampage occurred," Santa Barbara County Sheriff's Office spokeswoman Kelly Hoover said. Sheriff Bill Brown has defended the officers' actions, but the case highlights the challenges that police face in assessing the mental health of adults, particularly those with no history of violent breakdowns, institutionalizations or serious crimes. "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," Brown told CBS' "Face the Nation" on Sunday. "At the time deputies interacted with him, he was able to convince them that he was OK," he said. It's not clear why the deputies did not become aware of the videos. Attorney Alan Shifman said the Rodger family had called police after being alarmed by YouTube videos "regarding suicide and the killing of people" that their son had been posting. Doris A. Fuller, executive director of the Virginia-based Treatment Advocacy Center, said California law has provisions that permit emergency psychiatric evaluations of individuals who pose a serious threat, but that was never triggered. Rodger's family has disclosed their son was under the care of therapists. "Once again, we are grieving over deaths and devastation caused by a young man who was sending up red flags for danger that failed to produce intervention in time to avert tragedy," Fuller said in a statement. "In this case, the red flags were so big the killer's parents had called police ... and yet the system failed," she said. Rodger, writing in a manifesto, said he was relieved his apartment wasn't searched because deputies would have uncovered the cache of weapons he used in the beach town rampage Friday in which he killed six people and then, authorities say, himself. He posted at least 22 YouTube videos. He wrote in his manifesto that he uploaded most of his videos in the week leading up to April 26, when he originally planned to carry out his attacks. He postponed his plan after catching a cold. Because many of the videos were removed from YouTube then re-added in the week leading up to the killings, it's unclear which of the videos alarmed his family, or whether others were reported that were not uploaded again. In a last-minute bid to intervene, Rodger's parents raced to his home Friday night after his mother saw his online threats, but the couple heard the news of a shooting on the radio as they were on the freeway, the Los Angeles Times reported Sunday (http://lat.ms/1k7kdu6 ). Family friend Simon Astaire told the newspaper that Elliot Rodger's mother, Chin Rodger, got a call from her son's therapist shortly before the shooting started that he had emailed his ranting manifesto. Then, the mother found the YouTube video in which he threatens to kill people. She alerted authorities and set off frantically with her ex-husband, Hollywood director Peter Rodger. But by the time they arrived, officers confirmed their son had gone on a deadly rampage. Elliot Rodger played the video game "World of Warcraft," but the family never suspected he would have guns, said Astaire, who was speaking on behalf of the family. Investigators, including from federal Bureau of Alcohol, Tobacco, Firearms and Explosives, searched his parents' homes Sunday and left with boxes of evidence. In his videos and writings, Rodger voices his contempt for everyone from his roommates to the human race, reserving special hate for two groups: the women he says kept him a virgin for all of his 22 years and the men they chose instead. At least two other people who saw Rodger's videos before Friday compared him to a serial killer, through a message board on a bodybuilding website and the social network Reddit. The rampage played out largely as he sketched it in public postings, including a YouTube video where he sits in the BMW in sunset light and appears to be acting out scripted lines and planned laughs. "I'll take great pleasure in slaughtering all of you," the son of a Hollywood director who worked on "The Hunger Games" says in the video posted Friday and taken down by YouTube Saturday with a message saying it violated the site's terms of service. Brown told CNN on Sunday that investigators are close to having a "pretty clear picture of what happened." The first three killed Friday were male stabbing victims in Rodger's own apartment. The Santa Barbara sheriff's office identified them Sunday as Cheng Yuan Hong, 20, and George Chen, 19 -- both from San Jose -- and Weihan Wang, 20, of Fremont. They were all UC Santa Barbara students. Hong and Chen were listed on the lease as Rodger's roommates, and investigators were trying to determine whether Wang was a roommate or was visiting the night of the killings. Then, around 9:30 p.m., the shooting rampage began. Deputies found three semi-automatic handguns along with 400 unspent rounds in his black BMW. All were purchased legally.