“Sometimes we’ll be able to find other information from history, from the scene, from medical records that give us a clear cause of death,” coroner Barbara McLintock told CBC News.
“If it does not, and we think that the autopsy is the way to go to get that definite cause, then that’s when we go to autopsy.”
Investigators have already said there's no sign of foul play and no obvious indication of what caused the actor's death.
Police said Monteith had been out with people earlier, but video and electronic records from the hotel indicated he returned to his room by himself early Saturday morning. He was believed to be alone when he died.
'A true joy to work with'
Monteith is being remembered for his talent, friendly disposition and generosity — with several Vancouver-area charities, including Project Limelight, a drama and performance program for inner city children — saying Monteith's enthusiastic support will be sadly missed.
The Fox network and the producers of Glee, including 20th Century Fox Television, called Monteith an exceptional performer "and an even more exceptional person." They said he was "a true joy to work with and we will all miss him tremendously." Lea Michele, Monteith's Glee co-star and real-life girlfriend, asked for privacy upon hearing the news of his death.
While it's not known what caused his death, Monteith's passing recalls the lives of Heath Ledger, Corey Haim and River Phoenix — actors who battled substance abuse and died in their 20s and 30s.
Monteith talked bluntly about struggling with addiction since he was a teenager, calling it a serious problem and telling Parade magazine in 2011 he was "lucky to be alive."
Monteith admitted himself to a treatment facility in April for substance addiction and asked for privacy as he took steps toward recovery, a representative said at the time. It was not Monteith's first time in rehab. He also received treatment when he was 19.
"I think kids really need a place to go and feel like they belong," he said in the video posted the site for Project Limelight, a Vancouver charity offering theater and arts programs to at-risk youth.
"When I was a kid, I struggled a lot with who I was and where my life was going and what I was interested in. And I was fortunate to have the arts inspire me."
Fans leave flowers
Glee, with its catchy song-and-dance numbers and high-profile guest stars such as Gwyneth Paltrow and Britney Spears, became an instant hit when it debuted in 2009 and made celebrities of Monteith and the rest of the relatively unknown cast.
Over the past four seasons, he delivered renditions of such classics as U2's One and R.E.M.'s Losing My Religion.
Monteith played Finn Hudson, a football quarterback with two left feet who found more camaraderie in the choir room than on the football field.
After his character graduated high school, Hudson sought out to find himself before settling on what he wanted to do with his life: become a teacher and mentor.
Outside the Vancouver hotel where Monteith's body was discovered, a makeshift memorial popped up where fans left flowers and notes commemorating the actor.