Cory Monteith Cause of Death -- HEROIN AND ALCOHOL

3:10 PM PT -- Officials are currently addressing the media about the death investigation.

Cops wouldn't delve into specifics when asked if they found drugs in Cory's hotel room, but they certainly insinuated it ... saying, "There was evidence in the room that was consistant of a drug overdose."

Cory Monteith died from a lethal combination of heroin and alcohol ... this according to Canadian authorities.

The British Columbia Coroners Service says an autopsy and toxicological analysis show that the 31-year-old "Glee" star died from a "mixed drug toxicity, involving heroin and alcohol."

Monteith's body was discovered by staffers at the Fairmont Pacific Rim hotel in Vancouver, Canada on July 13.

Monteith had struggled with addiction for years and had been to rehab earlier this year.

Monteith had said he began struggling with drugs and alcohol as a young teenager.

Story developing ...