In the days leading up to murdering his mother, Barbara Waite, Ryan seemed to rehearse the crime.
On more than one occasion, he filmed himself on a GoPro, approaching the unsuspecting 64-year-old with a gun.
Then, on 31 March 2020, as the mum of two was playing piano at their townhouse in Squamish, he shot her in the back of the head.
Following the murder he would write in his private journal: "I'm so sorry mom, I'm so sorry Lisa [his sister] I hate myself.
"There's a lot of media of me out there […] film and TV […] hundreds of hours of me that can be viewed and dissected [...] No one will understand."
Still, he picked back up his camera and went on to describe the horrendous crime he'd committed: "I shot her in the back of the head.
"In the moments after, she would have known it was me."
Ryan covered his mother with a sheet, surrounded her with candles, and hung a rosary from the piano.
The Diary of a Wimpy Kid actor would spend the next few hours getting weed and beer, watching Netflix, and experimenting with making Molotov cocktails.
The next day, 1 April, Ryan rounded up the Molotov cocktails he'd made, three guns, ammunition, and camping gear, and was headed to Rideau Cottage, Ottawa, where Trudeau and his family are the current tenants.
The revelation was made during the actor's sentencing hearing this week, with CBC reporting that Ryan's police statement and private journal mentioned his plans to kill the Canadian prime minister.
However, before Ryan could carry out his plan, he has second thoughts.
This wasn't a change of heart just yet, as Ryan considered committing an act of mass violence at Simon Fraser University, where he'd dropped out of classes, or on Vancouver's Lions Gate Bridge.
Thankfully, Ryan would commit neither atrocity and handed himself in to police in East Vancouver that night, confessing to killing his mother.
That same evening his sister, Lisa, would find their mother's body.
Devastated, Lisa said: "How can I trust anybody when my only sibling chose to execute my mom when her back was turned."
In the months leading up to the crime, Ryan was said to have been struggling with feelings of anger and contemplating suicide. He is now facing a second-degree murder charge, which comes with a life sentence.
If you have experienced a bereavement and would like to speak with someone in confidence contact Cruse Bereavement Care via their national helpline on 0808 808 1677