Michael K. Williams' cause of death has been confirmed.
Nearly three weeks after the actor's death at age 54, the New York City Office of the Chief Medical Examiner announced Friday that Williams died by "acute intoxication by the combined effects of fentanyl, p-fluorofentanyl, heroin and cocaine."
The manner of death was ruled an accident.
The Wire actor was found dead in his Brooklyn penthouse apartment on Sept. 6, PEOPLE previously confirmed. Williams' nephew discovered his body in the living room.
Drug paraphernalia was found in the apartment, the New York Post reported. A separate law enforcement source previously told PEOPLE that Williams died of a suspected overdose and that officials believe he may have used heroin laced with fentanyl.
"It is with deep sorrow that the family announces the passing of Emmy nominated actor Michael Kenneth Williams," Williams' rep told PEOPLE at the time. "They ask for your privacy while grieving this unsurmountable loss."
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Over the years, Williams was open about his mental health and addiction struggles. Raised in the Vanderveer Projects of Brooklyn's East Flatbush neighborhood, he was exposed to crime at an early age and developed a drug addiction in his teens.
He told The New York Times in 2017 that although he'd had treatment for his addiction, he'd relapsed multiple times during his storied career. "Addiction doesn't go away," he said. "It's an everyday struggle for me, but I'm fighting."
HBO Michael K. Williams in The Wire
"I was playing with fire," he told NJ.com in 2012. "It was just a matter of time before I got caught and my business ended up on the cover of a tabloid or I went to jail or, worse, I ended up dead. When I look back on it now, I don't know how I didn't end up in a body bag. Eventually, I got so sick and tired of this charade. No one who was in my circle, who knew me as Mike, was allowing me to get high."
"I had to slip away to do drugs. I had to hide it. I'd be gone for days at a time. I was lonely in that part of my life. I was broke, broken and beat up. Exhausted. Empty," he continued. "I finally said, 'I can't do this no more.' I didn't want to end up dead."
Williams was laid to rest in Harrisburg, Pennsylvania, where his mother has lived for over two decades, on Sept. 15.
If you or someone you know is struggling with addiction, please contact the SAMHSA substance abuse helpline at 1-800-662-HELP.