Charles Manson’s devoted followers, the so-called Manson Family, was influenced by aspects of 1960s counterculture and lived a hedonistic, drug-filled lifestyle. At the center of what became a murderous cult was the music of the time—including some of the Beatles best-loved tracks. According to a series of interviews Manson gave over the course of his life, and in the testimony he gave at his 1970 trial and conviction for nine murders, the serial killer said hidden lyrics in songs on the album The Beatles, more commonly known as the “White Album,” inspired his family’s murderous acts.

Speaking to Rolling Stone in 1970, Manson said it was the Beatles who inspired the Tate-LaBianca murders in August 1969. “This music is bringing on the revolution, the unorganized overthrow of the establishment,” he said. “The Beatles know [what’s happening] in the sense that the subconscious knows.” At the scene of the LaBianca killings, one of the murderers used a victim’s blood to paint the words “Healter Skelter” on the refrigerator. It was a misspelling of Helter Skelter, one of the seminal tracks from the Beatles’ White Album, released in November 1968. In his account of his time in the cult, Manson family member Paul Watkins wrote that Manson began using the phrase “Helter Skelter” to refer to what he described as an oncoming race war. “What it meant was the Negroes were going to come down and rip the cities all apart,” Watkins recounted in My Life With Charles Manson. “Before Helter Skelter came along, all Charlie cared about was orgies,” he added. Manson also believed a series of other tracks made oblique references to race-related violence. The cult leader reportedly believed that the Beatles song “Piggies,” a satirization of bourgeois tastes, foretold of a Black uprising against the establishment. He frequently referenced the track “Revolution 9,” telling his followers that it contained the order to “rise” and referenced the Bible’s Book of Revelations. Similarly, he claimed the song “Blackbird” was an incitement by the Beatles for a race war. The family members wrote “Pigs” and “Death to pigs” in blood at the scenes of the killings, and cult members later described how Manson had explained the album’s significance in relation to the violence.

The Beatles all unreservedly dismissed the claims made about the album’s content. “He interpreted the whole thing…and arrived at having to go out and kill everyone.… It was frightening, because you don’t write songs for those reasons,” Paul McCartney said of Manson in the 2000 book The Beatles Anthology.

“It was upsetting to be associated with something so sleazy as Charles Manson,” George Harrison also said in Anthology.

Manson, who was convicted of nine murders in 1971, achieved unprecedented status in the years that followed as the most notorious American murderer of the 20th century. He died November 19 of natural causes at age 83, having spent the majority of his life inside penal institutions.