The long-awaited trial of former gay porn model Luka Magnotta finally began in Montreal yesterday, where Magnotta admitted for the first time to killing his former boyfriend.

Despite his confession, Magnotta plead not guilty to five charges related to the May 2012 killing of his boyfriend, Concordia University student Jun Lin. His lawyers have chosen an insanity defense, arguing that Magnotta is “not criminally responsible” for slaughtering, dismembering, and distributing his boyfriend’s extremities around town because he “didn’t know it was wrong.”

Magnotta initially claimed innocence when the crimes first snagged headlines. In May 2012, he became the primary suspect in his boyfriend’s murder after a video allegedly depicting the murder surfaced online.

According to prosecutors, Magnotta killed his boyfriend and then dismembered him, shoving his torso in a suitcase that was later found in a park near Magnotta’s apartment. Later, he mailed his boyfriend’s hands and feet to conservative Canadian politicians and two schools.

The CBC reports that Magnotta’s defense will seek to prove that he was schizophrenic at the time of the attack, and will need to argue that Magnotta was not capable of knowing right from wrong in order for him to avert prison time.

The case will be hard to prove, given new evidence shown in court that suggests the crime was premeditated and that Magnotta tried to clean the scene of the crime, two points that would imply he knew right from wrong at the time.

The details of crime scene photos, described by The Star, are beyond gruesome:

Initially, the apartment appeared to have been thoroughly cleaned and its contents removed. But a more thorough examination showed dozens of red stains that appeared to be blood, on the bathroom sink, bathtub, shower curtain, bathroom door, walls and on a dining room table. There were also flecks on a white heater next to the bed, as well as on the walls at the head and foot of the bed. Inside the refrigerator, there was blood on a shelf and a larger pool of blood that had collected under the produce drawer that may have been overlooked when the apartment was initially cleaned. The bed, the backdrop for the horrific murder video, was covered by a clean brown sheet, but underneath that, and a maroon plastic cover, were white stains where someone had attempted to bleach blood out of the mattress. It wasn’t successful, as there were still faint brownish-red marks beneath the bleach stains.

The trial will continue this week.