Canadian actor Cory Monteith died from a mix of heroin and alcohol in his system, the B.C. Coroners service has confirmed.

"Post-mortem testing, which included an autopsy and toxicological analysis, found that Mr. Monteith, aged 31, died of a mixed drug toxicity, involving heroin and alcohol," said a statement release by the coroner on Tuesday afternoon.

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"It should be noted that at this point there is no evidence to suggest Mr. Monteith's death was anything other than a most-tragic accident."

Monteith, 31, was found dead by staff at the Fairmont Pacific Rim on Saturday afternoon when he failed to check out of the hotel.

Vancouver police said because Monteith died alone in his hotel room there was no reason for any further police investigation, including attempting to identify and arrest the dealer who supplied the actor with the drugs.

"There is an inherent risk when you are using illegal drugs and there is nothing in these circumstance for police to investigate further," said Const Brian Montague.

"Unfortunately a mixture of alcohol and heroin can be fatal and this is another example of a tragic overdose. From the police perspective this investigation has been concluded," he said.

Police interviewed all three people who were out with Monteith the night before, and said the man and two women had co-operated with investigators.