The youngest member of Charles Manson’s “family” cult spoke out this week preceding the release of her new book. Dianne Lake, then 16 years old, was not part of the murders that left seven people dead in 1969 but heard about them from participants Susan Atkins and Patricia Krenwinkel.

“I was shocked,” Lake, now 64, told People magazine. “I was horrified.”

Further details about Lake’s life within the cult are detailed in her book “Member of the Family” due to be released October 24. Lake said she met Manson when she was 14 years old at a party in Topanga, California. She described Manson to People as “extremely intelligent” with the “incredible ability to pick up on other people’s weaknesses and their needs and their desires.” For Lake, that was her need for “love,” “affection” and “a family,” she said.

Manson founded his cult in 1967. His followers committed the now-infamous “Helter Skelter” murders in 1969. They killed seven people over the course of two days, including five at director Roman Polanski’s home. Abigail Folger, Wojciech Frykowski, Steven Parent, Jay Sebring, Sharon Tate and Leno and Rosemary LaBianca were all killed by the “family.” Manson was imprisoned in 1971 – where he has remained ever since. Now 82, he’s behind bars at Corcoran State Prison in California and has been denied parole 12 times.

Lake herself entered a psychiatric institution a year after the murders when she was 17 years old.

“You have the [Beatles’] White Album, throw in a little acid and drugs and a little Scientology and the Bible and stir it all up with a madman being the dance master,” said Lake. “It just went crazy. It escalated into horrible chaos, and I’m so glad I was not a part of it.”

She went on to testify against Manson and some of the other members of the cult in Los Angeles court. At some point in the trial, one of Manson’s dedicated followers, Susan Atkins, said the group was determined to be as gruesome and vicious as possible in order to shock the world.

“He just looked crazy," Lake told People of Manson's appearance at the trial. "But I was able to look at him. I had been pretty deprogrammed at this point, so I felt pretty safe.”

Lake went on to marry, have three children and pursue her master’s degree. She hasn’t spoken publicly about her time alongside Manson until now.

“I think the biggest burden was keeping it a secret,” she told People. “I survived and prevailed during this dark time.”