The US actor Philip Seymour Hoffman died from taking a combination of heroin, cocaine and other drugs, the New York City medical examiner has ruled,
The death of Hoffman, 46, who was found on February 2 with a needle in his arm on the floor of his Manhattan apartment, was ruled accidental.
He also had taken amphetamines and benzodiazepines, which are drugs such as Xanax and Valium that are widely prescribed for anxiety, trouble sleeping and other problems, said a spokeswoman for the medical examiner.
Addiction specialists say the toxic mix is not uncommon in the tens of thousands of overdose deaths in the US each year.
Dr Charles McKay, a medical toxicologist for Hartford Hospital in Connecticut, said: "There's a difference between a stimulant death, which would be cocaine and the amphetamines, and a narcotic death, like heroin."
The first two can cause heart rhythm problems, a stroke or heart attack, whereas heroin, especially with sedatives such as benzodiazepines, can depress breathing.
In any case, McKay said, the combination of drugs "suggests someone who has been using drugs repetitively".
Police had been investigating Hoffman's death as a suspected drug overdose. Tests found heroin in samples from at least 50 packets in his apartment, the AP news agency reported.
Authorities also found unused syringes, a charred spoon and various prescription medications, including a drug used to treat heroin addiction, a blood-pressure medication and a muscle relaxant.
More than half of overdose deaths in the US involve a mix of drugs, said Dr Len Paulozzi, a medical epidemiologist with the Centres for Disease Control (CDC) and Prevention.
At least a fifth also involve alcohol, he said. There were more than 38,000 drug overdose deaths nationwide in 2010, according to the most recent CDC figures.
Hoffman, who won an Oscar for "Capote" and starred in numerous other films as well as New York stage productions, had been frank about struggling with substance abuse.
He told CBS' "60 Minutes" programme in 2006 that had he used "anything I could get my hands on" before getting clean at age 22.
But in interviews last year, he said he had relapsed, had developed a heroin problem and had gone to rehab for a time.
A family spokesperson did not immediately return messages seeking comment, AP reported.
In his will, Hoffman bequeathed his estate to his longtime partner, Mimi O'Donnell, with a trust fund for their 11-year-old son. They also have two other children.
Investigators have been probing how Hoffman may have obtained the drugs.