Rapper Juice WRLD died from an accidental drug overdose of oxycodone and codeine late last year, The Chicago Tribune reports. The Cook County medical examiner’s office announced the 21-year-old’s cause of death on Wednesday, but said the full autopsy results and toxicology report was not yet complete. The full autopsy report could be released as early as Thursday. The rapper, also known as Jarad Higgins, died on Dec. 8 after suffering convulsions and going into cardiac arrest inside a private plane hangar at Midway Airport. Higgins’ girlfriend reportedly told police he had a drug problem and recently took Percocet and a painkiller. Percocet contains acetaminophen and oxycodone, an opioid that was reportedly found in Higgins’ blood.

Higgins and his entourage were stopped at Midway Airport so police could conduct a search of the plane, which they suspected had contraband on it. Officials reportedly found 41 bags of marijuana, six bottles of codeine cough syrup, three pistols, and a high-capacity ammunition magazine along with metal-piercing bullets. Two men identified as Higgins’ security detail were convicted of misdemeanor charges for the illegal possession of guns and ammunitions.