Published Friday, 28 February 2014
The tragic Capote star, 46, passed away from a suspected drug overdose at his New York City home on 2 February, but an initial autopsy proved inconclusive.
Officials at the city's medical examiner's office conducted further toxicology and tissue tests, and the results have since revealed he had anti-anxiety medication benzodiazepines and stimulants amphetamines in his system, in addition to the illegal substances.
The mixing of heroin and cocaine is known as speedballing - the same combination which killed comedian John Belushi and actor River Phoenix.
Hoffman's death has been listed as accidental, while coroners ruled the official cause of death was acute mixed drug intoxication.
The celebrated actor had struggled with drug abuse in the past and checked himself into rehab last year to battle an addiction to heroin after 23 years of sobriety.