Cory Monteith Drug Overdose Not Caused by 'Toxic' Heroin, Autopsy Results Show

The coroner who performed the autopsy on Cory Monteith revealed that the late actor did not overdose on a particularly toxic type of heroin that has been linked to an increase in overdose cases in the Vancouver area.

Local reports stated that law enforcement agencies around the area have issued a warning that a "toxic" mixture of heroin and fentanyl has been popping up, leading to an uptick in overdoses.

Autopsy results reveal that no fentanyl was found in the actor's system, and that a possible cause of his overdose was due to his low tolerance to the drug after entering a rehab facility in April, according to TMZ

The news has shocked not only the cast of "Glee," which Monteith was featured prominently in, but also those in the entertainment industry who were friends of the late star. Many expressed their deepest sympathies online.

Harry Shum, Jr., who plays Mike Chang, wrote, "At this time, please send nothing but love and light. This tragic news still doesn't feel real to me."

Former cast member Damian McGinty also reflected on his time working with Cory.

"The guy I shot my first acting scene with. The nicest guy I've met. Can't believe it," McGinty posted to Twitter.

A representative for Monteith's co-star and girlfriend Lea Michele released a statement asking for privacy as she comes to terms with her loss.

"We ask that everyone kindly respect Lea's privacy during this devastating time," the statement read.

"She is absolutely hysterical and completely inconsolable," a source told "She is devastated beyond belief."

While the "Glee" actors had been co-stars since 2009 when the show premiered, they didn't begin dating until 2012.