Grammy-winning rocker Tom Petty died of an accidental drug overdose, Los Angeles County Department of Medical Examiner announced Friday.

The medical examiner said the 66-year-old died of multi-system organ failure from cardiac arrest as a result of "mixed drug toxicity."

Officials found Fentanyl, oxycodone, temazepam (generic Restoril, a sleep aid), alprazolam (generic Xanax) and citalopram (generic Celexa for depression).

Petty's family said he was prescribed the medications to treat emphysema, knee problems and a fractured hip, which they said had recently progressed to a more serious break. They said he performed 53 tour dates with the hip injury.

"On the day he died he was informed his hip had graduated to a full on break and it is our feeling that the pain was simply unbearable and was the cause for his over use of medication," a statement on his official website said.

His family said they suspected he died of an accidental overdose and the coroner's report confirmed their beliefs.

"As a family we recognize this report may spark a further discussion on the opioid crisis and we feel that it is a health and necessary discussion and we hope in some way this report can save lives," the statement said. "Many people who overdose begin with a legitimate injury or simply do not understand the potency and deadly nature of these medications."

Petty died Oct. 2 at UCLA Santa Monica Hospital after his family decided to take him off life support. He had been found in full cardiac arrest at his manager's home.

Petty is best known as the frontman of Tom Petty and the Heartbreakers, which formed in 1978 and had hits such as "Mary Jane's Last Dance" and "Learning to Fly." He also had a solo career with hits like "Free Fallin'" and "American Girl."

He wrapped up a tour with the Heartbreakers on Sept. 25. Petty told Rolling Stone in December 2016 that the 40th anniversary tour would likely be his last large tour.

"On a positive note we now know for certain he went painlessly and beautifully exhausted after doing what he loved the most, for one last time, performing live with his unmatchable rock band for his loyal fans on the biggest tour of his 40-plus career," his family said. "He was extremely proud of that achievement in the days before he passed."

By Danielle Haynes, UPI.com

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