When former California Highway Patrol officer turned stay-at-home dad Gregg Musgrove started “treasure hunting,” the 56-year-old certainly never imagined he’d end up with a king’s bounty — the King of Pop, that is.

A trove of cassette and DAT tapes containing unreleased Michael Jackson tracks were found in a storage unit deep in the San Fernando Valley. Musgrove’s journey to the tapes began when an associate contacted him about a storage unit he’d recently bought in Van Nuys. The unit once belonged to Bryan Loren, a music producer and singer (whose current whereabouts are unknown, according to Musgrove).

On the tapes are 12 unreleased tracks, music Jackson worked on prior to the Dangerous album, around 1989 to 1991.

“I’ve gone to all the fan sites. Some of [the songs] are rumored to exist, some of them have been leaked a little bit,” Musgrove tells The Hollywood Reporter. “A couple aren’t even out there in the world.”

Musgrove’s full inventory list, pictured below, shows the collected tracks, along with snippets of other unreleased songs. Jackson, and presumably Loren, can be heard discussing the recording and creative process on the tapes. “I’m listening to this stuff, and I would get goosebumps because nobody’s ever heard this stuff before,” Musgrove says. “To hear Michael Jackson actually talk and kind of joke back and forth, it was really, really cool.”

Among the unreleased tracks is one titled “Don’t Believe It,” which seems to reference the rumors that would circulate about the pop star in the media. The vibe and style of the song is consistent with the kind of music Jackson was releasing at the time. On another tape, Jackson can be heard explaining the intended meaning of a song called “Seven Digits,” which references the identification number bodies receive in a morgue.

Perhaps one of the most fascinating tracks on the tapes is titled “Truth on Youth,” which is seemingly a rap duet between Jackson and LL Cool J. The rapper has spoken in the past about working with Jackson, confirming they had recorded music together. The song stands out for many reasons but largely due to Jackson rapping on it.

Unfortunately for diehard Jackson fans, it’s likely Musgrove will be one of the few people to ever hear these tapes. He and the attorney he brought on approached the Jackson Estate with their findings earlier this year. The estate, who Musgrove says did their own research into the tapes, declined to purchase the tapes for an unknown reason, but did provide him with an official letter stating that the estate does not claim ownership of these specific cassettes. They make it clear in the letter, however, that he and anyone else who might purchase these tapes down the line do not own the copyright on the recordings or the compositions, the estate does. Essentially, these tapes can never be released publicly.

In response, the Estate clarifies to THR that these tracks are not “new” as the master recordings are currently housed in the Estate’s vaults. “The Estate of Michael Jackson was presented with DAT copies NOT master recordings of Michael’s music, and we confirmed that the actual master recordings were in fact already located in the Estate’s vaults,” says a rep for the Estate. “It should be clear to all that ownership and rights of exploitation to the recordings remain vested in MJJP Records and that nothing commercial or otherwise can be done with the DAT copies.”

While the exact value of the find remains unclear — Musgrove and the team helping him believe it’s in the seven-digit range — he plans to take it to the four major auction houses in the near future. Perhaps one of the many celebrity Jackson memorabilia enthusiasts — Lady Gaga famously bought 55 pieces of memorabilia at auction — can add this to their private collection.

Dec. 12, 7:03 p.m. The physical tapes are not currently in Musgrove’s possession. They are in a secure facility under the control of his attorney.