Saskatoon man Thomas Hamp fatally stabbed his partner, but is he criminally responsible for murder?

Sask. man on trial for killing his partner WATCH: A Saskatoon judge is being asked to determine if a man who killed his girlfriend is criminally responsible for the death.

The second-degree murder trial of Thomas Hamp began Monday with the defence admitting Hamp fatally stabbed his girlfriend Emily Stanche on Feb. 20, 2022.

But defence attorney Brian Pfefferle says his client isn't criminally responsible for what happened on the third floor of their Main Street apartment that night.

"This is an issue of criminal responsibility and not an issue of a whodunit," Pfefferle said.

At the outset of Monday's trial day, Pfefferle argued Hamp's mental health is the key question to resolve at the centre of the case.

"Does he have the mental state for murder or is this a manslaughter," Crown prosecutor Cory Bliss asked the court.

An agreed upon statement of facts was read to the court Monday, where Bliss said Thomas grabbed a kitchen knife in the early morning hours on Feb 20, 2022 and stabbed Sanche in the upper left chest. The blade broke from the handle and remained lodged in Sanche's body.

She died 25 days later in hospital. Hamp was charged with aggravated assault at the time.

Hamp originally told a neighbour someone broke into the apartment and stabbed Sanche, before later admitting he stabbed her himself.

The first three witnesses called on Monday were the officers who first arrived at the scene. In the afternoon, two neighbours testified they heard a struggle and a call for help before finding Sanche laying in her own blood with Hamp crouched next to her.

Const. Adam Dottermann was shown a video and a series of photos from the scene after Hamp and Sanche were taken to hospital. One of the photos showed a psychiatrists' business card and a hospital bracelet Pfefferle says Hamp received after seeking help for mental illness days before the attack happened.

He says it was part of a series of attempts from Sanche and Hamp's family to get him help for escalating signs of mental illness.

"This is one of those situations that was completely unanticipated. Emily was repeatedly attempting to get the accused assistance in the weeks leading up to this. Her cries weren't answered until Feb. 20th," Pfefferle said outside of the courthouse.

Pfefferle said Hamp started to have delusions in the months and weeks prior to the attack. He was fearful of police and began experiencing things that "are just not formed in reality," according to Pfefferle.

He said Sanche would regularly update Hamp's father about his condition and some of the things that he was experiencing. She called him shortly before 2:30 a.m. — minutes before she was stabbed — asking Hamp's dad to come over because of her concern for Hamp's wellbeing.

By the time Hamp's dad arrived, Sanche was mortally wounded and police were on scene.

"It's just compounded tragedy," Pfefferle said. "Her kindness may have been one of the things that ultimately led to her being in a situation where this occurred."

Two weeks are set aside for the judge-alone trial. The Crown is expected to call more witnesses to testify Tuesday, but the trial isn't expected to be completed in two weeks.

A psychiatric assessment may need to be redone before an expert testifies. Pfefferle says he learned last month about letters intercepted by Saskatoon police which were written by Hamp in prison 18 months ago addressed to Sanche and other family members.

The expert may need to alter his assessment with the letters included, indicating a break may be necessary before that testimony takes place.