LOS ANGELES (REUTERS) - Rocker Tom Petty died in October due to "multisystem organ failure" brought on by an accidental overdose of seven medications, the Los Angeles County Medical Examiner's office said on Friday (Jan 19).

The coroner's office attributed Petty's death at the age of 66 to a "mixed toxicity" of fentanyl, oxycodone, temazepam, alprazolam, citalopram, acetyl fentanyl, and despropionyl fentanyl. The medical examiner's report lists the manner of death as"accidental".

Petty, whose vibrant guitar riffs, distinctive vocals and slick song lyrics graced such hits as Refugee, Free Fallin' and American Girl, was found unconscious at his home in Malibu on Oct 2 and died at a hospital later that night.

Petty, best known for his roots-infused rock music, carved a career as a solo artist as well as with his band The Heartbreakers and as part of supergroup The Traveling Wilburys.