The Los Angeles County Department of Medical Examiner - Coroner confirmed the star's cause of death on Monday. During the 911 call, his assistant said that Miller was "blue".
Mac Miller's death has been ruled an accidental overdose. The report further states that Miller was found in his bedroom with blood coming from one of his nostrils, and that cocaine residue, alcohol, and a prescription drug bottle were found by police.
The 26-year-old, who rose to fame after topping USA charts with his debut album in 2011, was found dead at his California home in September. Miller, whose real name was Malcolm McCormick, was found face down and unresponsive and paramedics pronounced him dead at the scene. The list of pills recovered in the home include Xanax, oxycodone, hydrocodone, and generic Adderall.
Miller's death came just months after he split from Ariana Grande and weeks after he was charged with a DUI.
"It is outrageous that Poisonous Synthetic Heroin Fentanyl comes pouring into the U.S. Postal System from China", he wrote on August 20.
An estimated 200 people die of overdoses every day, according to the US Drug Enforcement Administration. Fentanyl is a powerful opioid pain medication and is much stronger than heroin.