According to the admission of facts read out by the Crown, Ryan Grantham shot his mother Barbara Waite, 64, in the back of the head while she played piano in their Squamish townhouse on March 31, 2020.
The next day, while her body still lay in the pool of blood, Grantham loaded his car with three guns, ammunition, 12 Molotov cocktails, camping supplies and a printed Google map with directions to Rideau Cottage in Ottawa.
Grantham mentioned killing Trudeau in both his statement to police and in excerpts from his private journal that were read out in court.
The court heard how Grantham had escalating feelings of self loathing, hopelessness and a desire to commit violence in the months leading up to the murder. He was struggling with school, smoking a lot of cannabis, feeling angry and anxious over perceived failures, and contemplating suicide.
In the days before the murder, Grantham did a walk-through of the crime, surreptitiously approaching his mother with a gun on at least one occasion.
He also recorded himself on a GoPro camera. One video that was shown in court appears to show the walk-through. In another, taken on the day of the murder, he shows his mother's body and describes what happens.
"I shot her in the back of the head," he says. "In the moments after, she would have known it was me."
In his statement to police, Grantham said in the hours after the murder he freaked out, wrote in his journal, took the video, went out to get money, marijuana and beer, came home, experimented with making Molotov cocktails and watched Netflix for two and half hours. He then covered his mother's body with a sheet and went to bed.
The March 31 entry in his journal reads in part, "I'm so sorry mom, I'm so sorry Lisa ... 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," the journal reads.
Before leaving Squamish on April 1, he hung a rosary from the piano and arranged lit candles around the body.
Waite's body was found by her daughter on the evening of April 1. Lisa Grantham went to the home concerned after her mother failed to return phone calls and messages.
In her victim impact statement, Lisa Grantham said her life and career has been devastated by the murder. She said there is no doubt in her mind that her brother is a dangerous person.
"How can I trust anybody when my only sibling chose to execute my mom when her back was turned," she said to the court.
Second-degree murder comes with an automatic life sentence. The Crown is asking for 17 to 18 years of parole ineligibility.
Grantham's defence has yet to make submissions. The hearing will resume on Tuesday.