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LOS ANGELES - The LAPD on Thursday announced it has open investigations on a dozen unsolved homicides near known Manson Family hangouts around Los Angeles.

The revelation came amid a legal battle to obtain hours of audio tape recordings between former Charles Manson follower and convicted murderer Charles "Tex" Watson and his lawyer.

"We have an obligation to the families of these victims," Cmdr. Andy Smith told NBC4. "Our detectives need to listen to these tapes. The tapes might help with solving these murders."

News of the open investigation was first reported by the Los Angeles Times Thursday and confirmed to NBC4 by LAPD officials. Smith told the Times the 12 murders they are investigating "are similar to some of the Manson killings."

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Manson and his followers shot to infamy in 1969 after the murders of pregnant actress Sharon Tate and four others at a Benedict Canyon home in the hills above Los Angeles. That rampage was followed the next night by the murders of Leno and Rosemary LaBianca in their Los Feliz home.

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The unheard recordings sought by the LAPD were made more than four decades ago, after Watson’s arrest for his role in the Tate-LaBianca slayings.

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LAPD’s effort to obtain the tapes was not known publicly until it was reported by NBC4 News in May. And Watson has been fighting to keep those tapes under wraps. Police believe they may hold clues to "additional unsolved murders committed by followers of Charles Manson."

Earlier this year, a court order authorized LAPD to take possession of the recordings, but Watson’s lawyer obtained a "stay" order effectively stopping the release of the tapes while his appeal is heard.

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The LAPD tried to obtain the tapes using a search warrant, according to the Times. But on Oct. 9, a federal judge in Texas granted an emergency order barring police from executing a search warrant at an office where the tapes are kept.

For now, the tapes remain in the custody of a Texas bankruptcy trustee, who took responsibility for them after the 2009 death of Watson's original attorney, Bill Boyd. Boyd had made the recordings.

Watson, now 66, is serving a life sentence in California's Mule Creek State Prison in Ione, Amador County, outside Sacramento.