How he joined the cult: In March 1968, Paul met Manson at Topanga Canyon in LA, where many of the family members were staying. After spending the night with the group, Paul left. About three months later, Paul ran into two of the Manson girls in the San Fernando Valley in California, and went with them to Spahn Ranch. This time, Paul decided to stay, and he eventually became Manson's chief lieutenant.
Which crimes he committed: After being disturbed by Manson's remarks about Helter Skelter, Paul eventually decided to leave Spahn Ranch in 1969, before any of the murders took place.
What his sentence was: When the family was arrested in October 1969 for theft related charges, Paul went to the police. He ended up testifying against Manson in October 1970. He managed to live a pretty private life before dying of leukemia in 1990.