VIDEO: Watch a Sneak Peak of INSIDE THE MANSON CULT: THE LOST TAPES, Airing Tonight on FOX

Culled from more than 100 hours of footage, the two-hour special goes inside Spahn's Ranch, where the Manson cult lived, to offer an intimate and terrifying look into America's most murderous group.

Airing 10 months after Manson's death, the special features new and archival interviews with former Manson cult members, such as Catherine "Gypsy" Share and Dianne "Snake" Lake, as well as key people involved in the history of the Manson case, including prosecutor Stephen Kay and FBI criminal profiler John Douglas.

The special also features an exclusive interview with Bobby Beausoleil from prison, where he is serving a LIFE SENTENCE for a murder he committed in association with the Manson family. The exclusive special airs tonight (8:00-10:00 PM ET/PT) on FOX.