After reading Elliot Rodger's bizarre 141-page 'manifesto,' I'm convinced of two things. One, he was a narcissistic pipsqueak steeped in hate for everyone who wasn't him. Two, this tragedy was preventable if he weren't a rich entitled kid, or if his parents had been allowed to do more than stand by and call the police.

When Rodger's family notified the police about their concerns that he might turn violent, Sheriff's deputies paid Rodger a visit. They left convinced he wasn't going to do harm to himself, because he had a "very convincing story."

Anyone who watches that YouTube video has to wonder whether they were just taken in by his sense of privilege and entitlement. It sounds to me like he schmoozed them into thinking he was just fine, maybe writing a movie script or something, because Daddy was a line producer on The Hunger Games.

That visit could have scuttled the whole thing if deputies had checked to see if he owned firearms. In his manifesto, Rodger acknowledges that if the police had searched his apartment it would have put an end to his plan.

Writing of the visit, Rodger observed that a police search "would have ended everything." He went on to say "For a few horrible seconds, I thought it was all over."

But they couldn't search his apartment without probable cause. If they didn't know he owned guns, there was just a video which he explained away. On the other hand, knowledge of his gun ownership may have given them cause to search the apartment, which might have put an end to his planned violence.

According to reports, Rodger was also under the care of a therapist. In California, law enforcement and mental health professionals can force people who pose a danger to themselves or others into a 72-hour hold. Parents of adult children? Not so much. In fact, California law, as amended under Saint Ronnie's leadership, allows for people who might be subject to a 72-hour involuntary hold to be placed in the care of their family first.

But the key here is who can actually initiate a hold. In this case, it's either police or his therapist, and neither did so because he hadn't been violent in the past nor had he been held on an involuntary hold. So he was left to his own devices.

This happens too often, and in nearly every single case the warning signs are posted all over the Internet. Rodger was involved in the Men's Rights Movement, and had numerous postings in their online forums.

But in California, those who know these people best have absolutely no power to help them. Parents of adult children who they believe might do harm to others have no recourse other than to call the police and hope they find something.

I have seen this restriction in action too many times. Friends with a bipolar adult child had to call the police and have their child treated like a criminal to force him into treatment, instead of simply taking that initiative on their own. Once they're an adult, parents are robbed of any power to actually help them in a meaningful way.

There are no perfect answers to situations like this, but it seems to me that the parents were not taken very seriously when it came to their concerns about what he might have done.

Martha Raddatz took on this question on This Week With George Stephanopoulis. The transcript follows, via ABC News:

RADDATZ: Our thanks to Clayton.

Here now ABC contributor and former FBI special agent Brad Garrett and senior Justice Department correspondent Pierre Thomas. Thanks to both of you for joining us.

And Brad I want to start with you, we talked about these three interactions with police where deputies actually saw him, talked to him, the last was April 30. They went over there because his mother apparently had concerns about his safety, whether he was suicidal, had seen some videos -- not the one we just saw -- had seen some videos prior. Should deputies be determining the mental health of someone like that?

They basically said he was a polite kid and left.

BRAD GARRETT, FRM. FBI SPECIAL AGENT: At an alarming rate, law enforcement are being asked to be law enforcers and psychiatric social workers. And so when they are given a set of facts, they take them. And they look at the individual. They did an assessment by interviewing him apparently at his apartment. He was articulate, bright, lucid, not typically what they deal with day in and day out with people who have mental health issues.

And so it would appear that they sort of put it to rest at that point and felt like what else can we really do? He's acting normal. He's written some inappropriate things, but he didn't I guess withdrew them from the internet.

RADDATZ: Pierre, let me go to you, so what could law enforcement have done? Let me read from the manifesto that Rodger wrote, "as soon as I saw those cops, the biggest fear I had ever felt in my life overcame me. I had the striking and devastating fear that someone had somehow discovered what I was planning to do. If they had demanded to search my room, that would have ended everything." He said he had guns in his room. What could law enforcement have done? They didn't have a search warrant at that point.

PIERRE THOMAS, ABC NEWS CORRESPONDENT: Clearly they didn't have the predicate to search his room.

We talk about in covering terrorism connecting the dots. I think these things are happening so often now that police are going to have to be more proactive. The one thing that could have set this in motion, or stopped it, would have been to find out he had purchased weapons. You couple that with the fact that his parents are concerned about him being suicidal and you find out the man has actually purchased weapons. That might give them the predicate to do a search.

RADDATZ: Brad, Pierre talked about the parents. The parents were clearly concerned. They had social workers involved, therapists. What more could really a parent do. He was a 22-year-old?

GARRETT: Very little, Martha.

And the problem is that when you take an individual has no criminal history, has some mental health challenges along the way, has sort of found his way out of college, moving on, you know as a parent he's got problems. What am I going to do about it? And I think they were doing the best they could.

Once he becomes an adult, his ability to acquire firearms, to have all of these very, very dark thoughts. Until he takes some action and law enforcement knows in advance that he's about to take this action, there's very little they can do. And the parents are unfortunately sort of stuck.

Yes, they were sort of stuck. It seems to me that some basic national guidelines about involuntary commitment as well as firearms ownership would be helpful. But we can count on the NRA to block anything that might save lives. Because liberty.

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