Nanaimo woman guilty of graphic slaying & dismembering of former boyfriend

A Friday, July 19 verdict by veteran BC Supreme Court Justice Robin Baird in Vancouver heard he he wasn’t convinced Laroche intended to kill Mantee until she woke up at on March, 5 2020 at about 4 a.m. — thus in his view the premeditation factor required for a first degree murder conviction was not met.

“It was a matter instead of revenge,” Baird said, adding the evidence showed the brutal killing was also clearly not an act of self-defence.

Laroche confessed to the killing and dismembering Mantee’s remains to several people, including a pair of undercover police officers.

She detailed the graphic slaying and how she got rid of the remains within several minutes of meeting the officers at her Rosehill St. apartment unit in late April 2021.

Police taped off the apartment unit at 222 Rosehill St. which Laroche and Mantee shared. (file photo/NanaimoNewsNOW)

Laroche described she was estranged from the abusive Mantee, who was sleeping face-down on a living room mattress when she hit him multiple times in the back of the head with a small graphite sledgehammer.

Since a distressed Mantee was gurgling after being bludgeoned and didn’t die as fast as she hoped, Laroche slit his throat, dragged him to the bathtub and gutted him.

She placed his remains in the fridge and freezer of the ground-floor unit and told police she disposed of the body parts around Nanaimo.

“The violence of her attack was extreme and unmistakably punitive,” justice Baird said during his highly anticipated decision.

While Laroche will be handed an automatic life in prison sentence, it will be up to the judge to decide parole eligibility, which will be defined following a pending sentencing hearing.

Justice Baird stated the evidence showed Laroche was on the receiving end of emotional and physical abuse at the hands of Mantee.

He said Laroche was of the belief there would be a deady confrontation between the two one day.

“I find as a fact that Ms. Laroche turned in for the night, she set her alarm for an early hour the next morning because she had to go to work. Her plan for the day was to process fish, not kill Sidney Mantee,” justice Baird said during the tail-end of his hour-long ruling.

He swiftly discounted a self-defence argument, pointing to the defenceless position Mantee was in when he was drilled three times in the back of the head with the hammer.

No use of force was imminent against Laroche at the time, justice Baird noted.

“Ms. Laroche knew that he had no present capacity to harm or threaten her as she stood over him with her hammer. She acted unilaterally. It was entirely a one-sided transaction. Mr. Mantee was unarmed and defenceless. The level of violence that Ms. Laroche used was extreme and catastrophic.”

Lead defence attorney Glen Orris didn’t dispute her client killed and dismembered Mantee.

Orris unsuccessfully argued her client’s actions were unplanned and fell within the definition of self-defence and were at worst manslaughter.

Laroche and Mantee pictured together (Facebook)

The trial heard testimony from a close friend of Laroche, Robyn Bartle, who said Laroche confessed to the killing to her a little over 13 months later, indicating she’d beaten Mantee with a hammer.

Bartle, aware Mantee was previously a reported missing person, was under the impression he had moved to Victoria after the pair had split up.

She testified Mantee abused Laroche physically and emotionally.

The following day Bartle filed a report with Nanaimo RCMP, triggering the undercover police operation which initiated several days later at Laroche’s apartment unit.

Sidney Mantee , originally from Saskatchewan, was the focus of a missing person’s investigation several months after he was killed. (NanaimoNewsNOW/Nanaimo RCMP)

Confirmed bone fragments were found at Neck Point Park and Pipers Lagoon Park by police after Laroche took undercover police on site visits around Nanaimo where she pointed out where she dumped remains over the course of several months.

Laroche told police she placed Mantee’s remains into a backpack and used public transportation, as well as walked to various locations to dispose of his remains, including public washrooms.

She appeared to sound frustrated in secret conversations with police as she explained the frustration involved with portions of Mantee’s remains containing body fat not sinking in the ocean.

Investigators only managed to retrieve small amounts of Mantee’s remains.

Laroche admitted to disposing some of Mantee’s remains at the Hub City Fisheries plant where they had both worked together and originally met.

She cut him up into fine bite-sized pieces to allow fish the ability to consume the evidence, Laroche told undercover police.

Laroche relinquished the sledgehammer to police as well as tools and other items associated with dismembering his remains under the guise they could help her get rid of incriminating evidence.

Some of those items contained Mantee’s DNA.

Defence attorney Orris told the trial mistreatment by Mantee of one of Laroche’s cats the night before the killing put his client over the edge.

“She undertook the acts in order to defend herself…having been trapped in the situation she was in and feeling that way, she had no alternative,” Orris argued at trial.

Crown prosecutor Nick Barber stated while Laroche suspected her cat had been abused by Mantee, she couldn’t confirm it as fact before she slaughtered Mantee.

Barber argued Laroche’s actions were clearly pre-meditated and unreasonable.

“If she had been afraid or felt that she needed to act in self-defence there were so many options. She could have gone to work, gone to the authorities, or gone to friends or just done nothing because Mr. Mantee was asleep,” Barber argued at trial.

Barber referenced disturbing post-offence conduct by Laroche, including her use of the same knives she used to cut up Mantee to prepare herself meals.

Mantee’s case was long considered a missing persons file until the confessions to Bartle and then subsequently undercover police shifted the case to a homicide investigation.

Nanaimo RCMP conducted several searches around Nanaimo in the spring of 2021 for forensic evidence.

Laroche, who didn’t testify in her own defence, was arrested a second time with charges officially laid in March 2022.

She’s been in custody ever since.

Laroche, a former Wellington Secondary School student, unsuccessfully applied to be released on pre-trial bail last summer.

A lookout pier off the base of Newcastle Ave. near Laroche’s home is one of multiple locations she reported disposing of Mantee’s remains. (Alex Rawnsley/NanaimoNewsNOW)

“I broke him down piece-by-piece in the bathtub like an animal,” Laroche told undercover officers. (Submitted photo)

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ian.holmes@pattisonmedia.com

On Twitter: @reporterholmes

by Ian Holmes

Nanaimo woman guilty of graphic slaying & dismembering of former boyfriend

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