Cameron Pettit, one of three men charged with selling Mac Miller the drugs that led to the rapper’s fatal overdose, pleaded not guilty on Thursday.

According to the Associated Press, the 28-year-old man appeared in federal court with his attorney in Los Angeles. Prosecutors allege that Pettit sold the rapper “cocaine and pills that contained the powerful opioid fentanyl” shortly before he died last year.

Pettit was arrested in September. Two other men, Stephen Walter and Ryan Reavis, were also arrested later that month. All three face a minimum sentence of 20 years in prison if they are convicted.

Pettit has been in custody since he was arrested due to Instagram messages where he said he’d possibly leave the country.

According to reports, the indictment alleges that Walter, 46, was the one who provided Pettit with the cocaine and fentanyl, who in turn, sold it to the rapper. Reavis, 36, helped conduct the sale. Fentanyl is the cause of a growing number of overdose deaths in the country.

"It has become increasingly common for us to see drug dealers peddling counterfeit pharmaceuticals made with fentanyl," United States Attorney Nick Hanna said in a statement. "As a consequence, fentanyl is now the number one cause of overdose deaths in the United States. These defendants allegedly continued to sell narcotics after Mr. McCormick’s death with full knowledge of the risks their products posed to human life. We will continue to aggressively target drug dealers responsible for the spread of this dangerous chemical."