Influential music producer and convicted murderer Phil Spector, who notably worked on the Beatles' last album Let It Be, has died at the age of 81.

TMZ reports that Spector died from COVID-19 complications after he was transferred from his prison cell to a nearby hospital. He was diagnosed with the virus four weeks ago, and died on Saturday after he experienced trouble breathing. He was serving a 19-to-life sentence for the 2003 murder of actress Lana Clarkson, which he was convicted for in 2009. She was killed inside of his California mansion, and prosecutors indicated that he previously had pulled guns on four different women.

Prior to his conviction for second-degree murder, Spector built a name for himself in the '50s as part of the Teddy Bears, later working with the Ronettes, and Tina Turner in the '60s. He produced the Beatles' final studio album Let It Be, and worked with both John Lennon and George Harrison in the decade that followed. Other acts that he wrote or produced for include Leonard Cohen, the Ramones, and the Righteous Brothers.

Perhaps his largest contribution to the world of music came with his "Wall of Sound" production technique, which he developed to create a fuller, more dense sound. The technique went on to influence countless musicians including the Beach Boys, Brian Eno, Bruce Springsteen, and My Bloody Valentine. He was inducted into the Rock and Roll Hall of Fame in 1989, and the Songwriters Hall of Fame in 1997.

Al Pacino portrayed Spector in the 2013 HBO film Phil Spector alongside Helen Mirren.