Even 40 years after the infamous Manson Family murders, parents worry if their own children could be influenced by a cult leader like Charles Manson.

It was an abrupt shift when the Summer of Love turned into the Summer of Fear. On August 9, 1969, masterminded by Charles Manson, members of his "Family," a group of disenfranchised young men and women, went on a two-day killing rampage that left seven people dead, including pregnant actress Sharon Tate. The killings were so horrific -- most of the victims were stabbed multiple times -- that four decades later, the murders are still considered the pinnacle of evil.  

The band of killers dispatched by Manson, an ex-con and con man, were barely out of their teens. Some came from what would be considered "good" homes. Leslie Van Houten, 19 at the time of the murders, was a former homecoming queen. Others, like Charles "Tex" Watson, 24 years old when he announced to his victims, "I'm the devil and I'm here to do the devil's work," was an All-American boy who, before he met Manson, was a straight-A student and high school football hero. What all the Manson Family members had in common was a desire to find meaning in their lives and feel a sense of belonging. And they thought Manson had all the answers.

Of course, parents would like to believe their children would be incapable of such heinous crimes, or of blindly following a man who touted peace and love while simultaneously instigating random violence he called Helter Skelter. Manson himself deflected all blame right back at the parents in his 1970 pretrial testimony:

"You made your children what they are. These are your children. You taught them. I didn't teach them. I just tried to help them stand up."

Nobody wants to take parenting advice from a mass murderer, but Manson's statement does drive the point home that parents must be vigilant to keep their kids on the right track -- far away from the Charles Mansons of the world. But how?

"Teen rebellion is a part of life," says Robin Sax, a former Los Angeles County deputy district attorney, and author of Everything I Know About Parenting I Learned in Court: How To Raise Disciplined Kids. "Whether or not it goes to the extreme, there are always signs to look for." Teens with low self-esteem who isolate themselves, cutting themselves off from society or even from their school, might be at risk, says Sax. Add to the mix "a leader who insists his belief system is better than anyone else's," and followers who are forbidden to question him -- and you've got a recipe for disaster. 

"With the advent of social networking sites like Facebook and MySpace," says Sax, "cult recruitment is easier than ever." The teen years are a time to explore; teens are inherently vulnerable and curious. The Internet, says Sax, allows one to try different philosophies "on for size." "Before they know it," warns Sax, "what can seem harmless at first because of the passivity of the 'net can draw a kid in -- and sometimes it's hard to get out."

One can only wonder how much more Manson could have done if he had had his own Facebook page back in 1969. Hopefully he'll never be able to get one -- his next parole hearing is scheduled for 2012. Manson has been denied parole 11 times.

Robin Sax is a former Los Angeles County Deputy District Attorney who specialized in prosecuting sex crimes against children. She is the author of six books including "Predators and Child Molesters: What Every Parent Needs to Know To Keep Kids Safe." Robin is a regular legal commentator on Larry King Live, Nancy Grace, Fox News and has a weekly radio show, "Justice Interrupted." Robin lives with her husband and three children in Los Angeles, California.mo