The coroner categorized the death as an accidental overdose.
He was found in his bedroom in the San Fernando Valley around 12 PM. Specifically, fentanyl, coke and alcohol were found in his system.
The coroner classified the overdose as accidental, TMZ reported.
The report said that Miller's assistant found him unresponsive on his bed in a "praying position" and was kneeling forward with his face on his knees. A rolled up $20 bill with white powdery residue was also found in his right pocket.
Shah Rukh Khan’s birthday party stopped by Mumbai police
At the launch, SRK was present along with the leading ladies of the film Anushka Sharma and Katrina Kaif on the dais. While the restaurant shut for the general public at 1 am, it remained open for Shah Rukh Khan's private party.
A person close to Miller, whose real name was Malcolm James McCormick, said he had spent the evening watching football. He had a history of drug and alcohol abuse, but his mother told investigators he had not overdosed in the past to her knowledge, or been hospitalized for any reason. Officials pronounced him dead at the scene. The concert included performances by Anderson.Paak, ScHoolboy Q, Alchemist, Action Bronson, Vince Staples, Chance The Rapper, Earl Sweatshirt, SZA, Travis Scott, Ty Dolla Sign, John Mayer, and Swimming collaborator, Thundercat.
Miller's death came just months after he split from Ariana Grande and weeks after he was charged with a DUI.
Fentanyl, a powerful painkiller that tends to be cheaper and more potent than heroin, has played a major part in the USA's opioid crisis.