Cory Monteith, who played an upbeat and outgoing young student and singing coach on the hit Fox musical comedy series “Glee,” was found dead on Saturday in a hotel room in Vancouver, British Columbia. He was 31 and had struggled with substance abuse.

[“Glee” actress Naya Rivera missing at California lake.]

Mr. Monteith’s body was found in his 21st-floor room at the Fairmont Pacific Rim hotel around noon after he missed his scheduled checkout time, the police said. They said they believed he was alone when he died.

The British Columbia’s coroners service announced on Tuesday that the cause of death was “a mixed drug toxicity, involving heroin and alcohol.”