Autopsy result of 31-year-old hit television series Glee star Cory Monteith reveals that the actor died due to a lethal combination of heroin and alcohol.

Monteith was found dead in a 21st floor room at the Fairmont Pacific Rim Hotel in Vancouver, Canada on Saturday by the hotel staff.

According to The British Columbia Coroners, the investigation into the We are Young singer's death is still on and that no other information is available at the moment.

"There was evidence in the room that was consistent of a drug overdose," Police Constable Brian Montague said, according to a Mail Online report.

Police officials initially said that they didn't believe the cause of the actor's death was drug overdose.

"It was the opinion of the investigators that it was a drug overdose, but we didn't want to speculate," Montague said.

"The last thing we would want to do is speculate a drug overdose and then have that not be the case," he added.

Police also confirmed initial reports which suggested that Monteith was alone in his room at the time of his death. A report in CNN said that though Monteith did go out on Friday night, he returned to his room alone on early Saturday morning.

"Mr. Monteith was alone [in his hotel room] when he died," a Vancouver Police Department spokesperson said. "He took the heroin when he was alone by himself," the spokesman added.

Three individuals who left Monteith's room on Friday night at about 2:15 a.m are being questioned by the Police Department. "They were all cooperative," a Police representative said, adding that no arrests in connection to the actor's death have been made.

Cory Monteith had drug related problems ever since his teenage. The actor had also checked himself into a rehab facility, for substance abuse in April this year.

Meanwhile, Monteith's girlfriend, Glee co-star, Lea Michele released a statement through her representative on Monday.

"Lea is deeply grateful for all the love and support she's received from family, friends, and fans. Since Cory's passing, Lea has been grieving alongside his family and making appropriate arrangements with them," the 26-year-old's representative told People.

"They are supporting each other as they endure this profound loss together. We continue to ask the media to respect the privacy of Lea and Cory's family," the representative added.