Phil Spector, the famed Wall of Sound producer who spent the last 11 years in prison for a murder he committed in 2003, died Saturday, the California Department of Corrections and Rehabilitation has reported. He was 81.

No cause was given, but news outlets are reporting that Spector had been suffering from COVID-19 and had been moved to a hospital for treatment.

Famous for producing and/or co-writing hits such as The Crystals’ “He's a Rebel,” The Ronettes’ “Be My Baby” and The Righteous Brothers' “You've Lost That Lovin' Feeling,” Spector also produced The Beatles’ final album, Let It Be, and worked with John Lennon, George Harrison, The Ramones and Leonard Cohen after his style fell out of favor. He had 24 records in the Top 40 between 1960 and 1965, 13 of them in the Top 10.

The influence of the sound of his early '60s records—cavernous and rich in reverb, symphonic and rhythmic, and heavy on the layering of voices and instruments—has run deep, from The Beach Boys to Bruce Springsteen to punk rock and beyond. With the vocals of Ronnie Spector, Darlene Love and a handful of others, Spector pioneered the harmony-rich girl-group sound that has never gone out of favor.

Spector, who lived in a castle in Alhambra and had a history of threatening people with guns, was convicted in 2009 of the murder of actress Lana Clarkson. He was serving a 19-year sentence.

As a high school student in Los Angeles, Spector scored a #1 single in 1959 with his trio, The Teddy Bears, “To Know Him Is to Love Him,” a do-wop-inspired ballad that took its title from the inscription on the tombstone of Spector’s father.

Spector moved to New York at the age of 19 to work with Jerry Leiber and Mike Stoller—he co-wrote “Spanish Harlem,” played the guitar solo on “On Broadway” and produced Ruth Brown, LaVern Baker and Gene Pitney before returning to L.A.

Once back, he formed the Philles label with Lester Sill and started cracking the Top 20 in 1962 with The Crystals’ “There’s No Other (Like My Baby),” which was followed by “Uptown” and “He’s a Rebel.” Bob B. Soxx and the Blue Jeans’ “Zip-a-Dee-Doo-Dah,” The Crystals’ “Da Doo Ron Ron” and “Then He Kissed Me,” and The Ronettes’ “Be My Baby,” “Baby I Love You” and “The Best Part of Breaking Up” would follow in late ’62 and 1963.

In 1964, Spector started working with the Righteous Brothers (Bill Medley and Bobby Hatfield), producing one of the biggest hits of the 20th century, “You’ve Lost That Lovin’ Feelin’,” plus the Top 10 “Just Once in My Life,” “Unchained Melody” and “Ebb Tide.”

By 1965, however, The Beatles, The Rolling Stones and other British acts were filling the charts and AM airwaves alongside Motown artists and The Beach Boys, whose “Don’t Worry Baby” was among the Brian Wilson-penned hits bearing the unmistakable imprint of Spector.

Spector felt he had a masterpiece on his hands when he went to Gold Star studio to record “River Deep, Mountain High” with Ike & Tina Turner in early 1966. Released in May 1966 at great expense, the single peaked at #88 and was off the chart four weeks later. Though it failed to connect commercially, it has since been hailed as the masterpiece Spector envisioned.

He laid relatively low until 1969, when he was tapped to put finishing touches on the final Beatles LP. Paul McCartney took issue with some of Spector's work, the strings on "The Long and Winding Road" in particular, but in 1970, the producer was asked to oversee Lennon’s “Instant Karma.” That success led to his handling the Lennon albums Plastic Ono Band, Imagine, Sometime in New York City and Rock & Roll.

In addition to Lennon, former Beatle Harrison had Spector produce his three-LP set All Things Must Pass and the Concert for Bangla Desh album, which won the Grammy for Album of the Year.

Despite those high-profile projects, Spector’s workload declined. Cohen had him produce Death of a Ladies Man and The Ramones called him in for End of the Century, but both acts took issue with his undisciplined handling of firearms. Following Spector's death, Blondie's Chris Stein tweeted: "When we went to Phil Spector's house in the '70s, he came to the door holding a bottle of diet Manischewitz wine in one hand and a presumably loaded 45 automatic in the other."

Reissues, a revived interest in his 1963 Christmas album, a documentary and a biography kept Spector’s name afloat through the ‘80s and ‘90s. He was inducted into The Rock & Roll Hall of Fame in 1989.

He produced a couple of songs for the band Starsailor in 2003, which went nowhere, and was rumored to be working with Celine Dion.

Spector was arrested in 2003 at his mansion, where Clarkson, a hostess at the House of Blues who had spent the night partying with him, was found dead. After his first trial resulted in a hung jury, Spector was found guilty at a second.

He is survived by a son and daughter.