Larry Melton aka White Rabbitt.  Manson Family who was the main source for the book "The Family" written by Ed Sanders and published in the early 1970's.

One page handwritten letter sent to Melton while he was incarcerated in a Texas prison. This was written when Melton was still attempting to recruit people for whatever it is he had going on under the guise of recruiting them to join the Manson Family. 

Letter with Envelope to Larry Melton Manson Family Recruitment