Police were engaged in a lengthy court battle over the tapes that captured Charles Watson, a member of the Manson family, and his lawyer discussing the cult's actions. Watson authorized his lawyer to sell the tapes to an author who wrote a book on the Manson family.
Prosecutors successfully convinced U.S. District Judge Richard A. Schell that Watson had waived his attorney-client privilege when he authorized his lawyer, who died in 2009, to sell the tapes, the Los Angeles Times said Friday.
The Manson family, led by Charles Manson, was linked to nine killings in 1969 in Southern California.
Manson has bragged there are killings for which he and his followers escaped blame, and authorities have speculated there are at least six other deaths around that time that remain mysterious or unsolved -- and that could be linked to the Manson family.
Watson is serving a life sentence for his role in the Manson family killings of Sharon Tate and four others in a rented Benedict Canyon home, using Tate's blood to write "PIG" on the front door.