Ryan Grantham, an actor on 'Riverdale' and 'Diary of a Wimpy Kid,' sentenced to life in prison for murdering his mother

• "Riverdale" actor Ryan Grantham was sentenced to life in prison for murdering his mother.
• The Canadian actor shot his mom with a rifle while she played the piano in 2020.

Ryan Grantham, an actor who appeared on "Riverdale and in the 2010 movie "Diary of a Wimpy Kid," was sentenced to life in prison after pleading guilty to the second-degree murder of his mother Barbara Waite at their home in Squamish, British Columbia, in March of 2020, CBC reported on Tuesday.

The Canadian actor, who was 21 at the time of the crime, confessed to shooting Waite in the back of her head with a .22 rifle while she played the piano. Shortly afterward, he took a GoPro video (shown in court) confessing to the murder and showing his mother's body. The next day, he covered her body with a sheet and surrounded it with lit candles, according to CBC, and also hung a rosary from the piano.

The court heard that Grantham then got into a car with guns, ammunition, and Molotov cocktails. He was headed to Ottawa with the intention of killing Canada's Prime Minister Justin Trudeau, CBC reported.

Instead, the actor turned around and headed toward Hope, British Columbia, with "thoughts" of committing mass murder at Simon Fraser University, where he was a student at the time, or Lions Gate Bridge, according to CBC.

Grantham didn't act on those thoughts and turned himself into the Vancouver Police Department in East Vancouver later that night.

Justice Kathleen Ker said while reading her sentencing decision that it was a "saving grace" that Grantham decided not to commit a mass shooting. He was charged with second-degree murder, which carries an automatic life sentence in Canada, and will be eligible for parole in 14 years.

He was reportedly having mental health issues and was "consumed" by suicidal and homicidal thoughts around the time of the murder. He was also watching violent videos on the dark web, according to the CBC.

Ker said there were mitigating circumstances involved in her sentencing decision, including the fact that Grantham appeared to be genuinely remorseful about killing his mother when he apologized for his actions in June. Ker also said he's receiving psychiatric help in prison and the CBC reported that he's receiving "positive reviews" on his progress.

In response to a Variety article reporting on the sentencing on Friday — in which the outlet referred to Grantham as a "Riverdale actor," "Riverdale" star Lili Reinhart tweeted to the outlet: "We do not claim him, thank you."

Grantham only appeared in one episode of "Riverdale" as Jeffrey Augustine, a character who accidentally kills Fred Andrews (main character Archie's father and played by the late Luke Perry) in a hit-and-run after stealing his father's truck. The episode premiered in 2019.