Ana Paula Kitterhing De Sousa never missed a text message from her daughter.
But when Raquel Almeida Margulies texted a habitual “sweet dreams, mama,” at 10:28 p.m. on Oct. 15, 2023, the text was left curiously unanswered.
At 9:25 a.m. the next day, Raquel began to worry. “Ola, mama,” she texted again. No response.
The reason came later that morning when two Toronto police officers appeared at Margulies’ door. They asked her if she knew Ana Paula De Sousa.
“And then I knew,” says Margulies.
The night before, De Sousa had been stabbed to death by her ex-boyfriend, Michael Calvo.
Yet he would never face a criminal trial.
Two years after the killing, while Calvo was in custody awaiting trial, two psychiatrists determined that he had been suffering from a schizoaffective and opioid use disorder when he stabbed De Sousa 26 times.
As a result, Calvo was declared “Not Criminally Responsible” (NCR) by a court in October 2025.
“Not Criminally Responsible” is a finding that the accused has committed the crime but cannot bear criminal responsibility for it because they were unable to appreciate the wrongness of their actions due to mental illness. Killings that are found to be “NCR” make up an average of about three per cent of all homicides annually in Canada, data compiled by the Investigative Journalism Bureau shows.
De Sousa’s case is among 159 killings between 2018 and 2025 in which the perpetrator was determined to be NCR.
The IJB’s analysis of these cases reveals three major themes: repeated failures by the health-care system to act in the face of persistent red flags before the killings took place; the conspicuous role of cannabis as a unique driver of the mental-health crises that result in fatal violence; and the disproportionate targeting of women — especially mothers — who are killed after making repeated pleas to health-care workers to help their mentally ill child.
In about one-quarter of cases — 42 out of 159 — the perpetrator had been seen by a health-care worker about their mental health in the month before the killing. Fourteen of the killings happened within hours of that health-care intervention.
In 56 out of the 159 cases in the IJB’s database, cannabis was identified as a contributing factor to the onset or deterioration of the accused’s psychosis — a brain condition that renders the individual unable to understand what is real — according to the IJB’s analysis of court and review board transcripts.
The data shows women and girls are almost twice as likely to be victims in NCR killings as they are to be among homicide victims in general. They account for 46 per cent of the 159 victims in the IJB database, compared to 25 per cent (on average) of all homicide victims, according to Statistics Canada.
The data also highlights disturbing patterns in the time between the accused’s last contact with a health-care professional and when the killing took place.
NCR a controversial finding
The assessment to determine if a person can be found Not Criminally Responsible evaluates the accused’s mental state at the time of the crime.
It can be requested by the Crown, the defence or ordered directly by a judge, and is conducted by a forensic psychiatrist. It can take place ahead of trial or following a criminal conviction.
If the NCR assessment concludes that serious mental illness rendered the accused incapable of understanding the nature and wrongfulness of their actions, the defence argues an NCR finding should be made. The submissions are then legally tested in court, and the final decision to find someone NCR rests with the court.
If the NCR assessment was requested by the defence, the Crown can, and often does, retain its own forensic psychiatrist to conduct a second assessment.
In many cases, the IJB has found, the submissions for an NCR finding are made jointly by the Crown and the defence.
If the court finds an accused to be NCR, the person does not go to prison but instead is put in the care of a forensic mental health hospital, a secure facility that treats individuals with serious mental illnesses who have come into contact with the criminal justice system.
Each year, the patient’s status is reviewed by a provincial review board, which consists of hospital staff, attorneys, psychiatrists and a representative of the Attorney General. The review board evaluates their privileges and possible risk to the public. In many cases, they may be held in treatment for years. In many other cases, the person is eventually released.
Sometimes there are oversight conditions attached to this release. In other cases, there are no conditions for mandatory follow-up on release. This is known as an absolute discharge.
Some families of victims have expressed frustration with the systemic failures leading to the killing of their loved ones, and criticized what they feel is a lack of transparency around how NCR verdicts are reached and the inability to hear all the evidence in court.
In June, British Columbia Premier David Eby said the NCR system “is not working” and “re-victimizes the family that was affected,” after a man found NCR for the killing of his children in 2008 received a conditional discharge earlier this year.
Many experts who work inside forensic medical systems say that the issues around NCR findings are complex.
“Essentially every time that somebody is found NCR, that’s a failure of the civil mental health system because these people are known and they’ve fallen through the cracks,” says Dr. Patrick Baillie, a psychologist in an outpatient forensic program (Recovery Alberta) in Calgary.
“It’s unfortunately quite common” that individuals who are later found NCR have had “very recent contact” with the mental-health care system before they offend, says Richard Schneider, a clinical psychologist and a judge at the Ontario Court of Justice.
Schneider presided over Toronto’s Mental Health Court — a criminal court dedicated to those with serious mental health illnesses who are facing criminal charges — for many years.
He gives the health system a grade of C- on its ability to spot the red flags that could indicate a mentally ill person might pose a physical threat to others.
The IJB found one family attempting to hold the civil system to account in a $2.5-million lawsuit.
Melissa Duff-Shore had at least seven interactions with the Waterloo, Ont., mobile crisis team in the three weeks before she killed her 22-year-old daughter, Kayla Duff-Foley in 2020, according to the statement of defence filed by the Waterloo branch of the Canadian Mental Health Association (CMHA WW), named in the lawsuit.
Duff-Shore was declared NCR in May 2024.
Her mother and surviving daughter are now suing the police and CMHA WW, alleging the systems “showed a callous disregard and complete lack of care for the safety of the late Kayla Duff-Foley.”
They allege police and emergency responders had “talked Melissa Duff-Shore out of leaving her home despite her verbalized homicidal ideation … despite her repeated pleas for help,” the statement reads.
The statement of defence filed by the CMHA WW denies these allegations or “that there was any breach of duty, want of care or negligence on its part.” The mobile crisis team has contacted Melissa’s pharmacy to request a list of her medications a day before the killing, the statement of defence reads.
In response to the IJB’s questions about what protocols the CMHA WW relied on when responding to Duff-Shore’s pleas for help, organization spokesperson Megan Brandy declined comment, citing privacy and the fact that the matter is before the courts.
Duff-Shore’s mother and surviving daughter declined comment. Melissa Duff-Shore, contacted through her defence lawyer, did not respond to a request for comment. The Waterloo Regional Police Services did not respond to questions.
One 2015 study found that for someone who has gone through the forensic medical system after being found NCR, the likelihood of reoffending is dramatically lower than for offenders in the correctional system.
The study also says that an “NCR verdict does not mean the individual gets an ‘easy ride.’ In fact, quite the contrary as many NCR individuals actually spend more time in a mental health hospital than they would have spent in jail if convicted of a crime,” it concludes.
Fifteen people in the IJB’s database who were found NCR for a killing had been previously found NCR for other non-fatal crimes, such as assault, uttering threats and failing to comply with a court undertaking.
One of those was 20-year-old Josué-Nathan Weizineau . In 2020, Weizineau shot and killed his father while on a hunting trip, just a few months after receiving three separate NCR verdicts for acts of violence against several people, including pointing a firearm at a person.
It is unclear what, if any, conditions stemming from previous NCR findings Weizineau was under at the time of killing his father.
Weizineau was found NCR for his father’s killing in June 2022. He declined to comment on his NCR finding or his current condition.
Red flags missed
Twenty-five killings in the IJB database happened on the same day as a mental-health intervention.
Eleven of those involved police who conducted a wellness check or received a call about the accused’s behaviour.
Emily Appleyard called police for a wellness check for her boyfriend, Andywele Mullings , on the day he attacked her.
Mullings had been exhibiting paranoid delusions for weeks. He had recently spent a night in jail and was telling family and coworkers that Appleyard was trying to kill him.
The police found Mullings “not making sense,” “rambling” and sounding “possessed,” according to court records.
Nevertheless, they declined to apprehend him under the Mental Health Act, which gives police the power to take someone into custody without a warrant if they have a reasonable belief that a person has a mental disorder and presents a risk of imminent harm to themselves or others.
But the police did get Mullings to agree to go to a Vancouver emergency room, where a nurse determined that he needed “rapid medical attention” from a psychiatrist.
However, instead of getting care, Mullings was allowed to walk out of the ER at Vancouver Coastal Health Lions Gate Hospital.
One hour later, he returned to the home he and Appleyard shared and, within three minutes, had attacked Appleyard with a hammer.
She died of her injuries days later.
Mullings was charged with second-degree murder, but was never criminally convicted. A court found him NCR in 2023, concluding he had suffered from untreated schizophreniform disorder at the time he killed Appleyard.
The IJB did not receive a response to questions from Mullings’ lawyers, or from Lions Gate Hospital.
One of the conundrums facing health-care workers is that most people presenting to emergency rooms for mental-health issues don’t, in fact, go on to commit violence, says forensic psychiatrist Michael Seto of The Royal Ottawa Health Care Group. “It’s really hard to predict those super rare events.”
Still, he sees “opportunities for early intervention.”
“In a frontline situation, there is some key information that we should get that is really helpful in terms of identifying when we need to hold on to somebody, or when we need to be more actively intervening,” Seto says.
That includes identifying any history of violent altercations, substance misuse and paranoid delusions directed at specific people, such as caregivers.
“We do have valid methods for assessing risk of violence, but all of those require having adequate information and the time to do it properly,” says Seto.
“I don’t know about you, but my doctor visits are 10 minutes long. They’re not going to have the training or the information or the capacity to be able to do some kind of effective screening.”
The role of cannabis
Since 2018, prolonged cannabis use has been cited as a factor in the onset or deterioration of psychosis in 35 per cent of NCR killings: 56 out of 159 cases.
All but two of these 56 accused were male — most of them under 35 years old.
In 15 of the cases the IJB reviewed, substance use was cited by expert psychiatrists as the primary trigger for psychosis, which led to the fatal violence. Cannabis was usually paired with other substances, most frequently alcohol and cocaine.
A 2024 study from the International Journal of Drug Policy shows a two-to three-fold increase in the relative risk for psychosis among users of cannabis.
It also states that Canada’s legalization of cannabis came “without sufficient consideration of the potential impact on vulnerable persons such as youth and those with serious forms of mental illness.”
In addition, current forms of cannabis are more potent than in the past, experts say. The Canadian Medical Association Journal says the potency of cannabis has “roughly quintupled in the past two decades, from around four per cent in the 2000s to more than 20 per cent in most legal dried cannabis in Canada by 2023.”
It also notes that high-potency, regular cannabis use has been linked to a higher risk of psychosis, and that this can increase the risk of schizophrenia.
Thomas Hamp says he used cannabis from the time it was legalized in 2018 until two days before he stabbed his girlfriend, Emily Sanche, in the chest with a kitchen knife in February 2022.
Hamp was charged with second-degree murder, but was later assessed by a psychiatrist, who concluded that he was on the schizophrenia spectrum and had a cannabis use disorder.
Hamp was found NCR for Sanche’s killing in 2025.
In an interview with the IJB from the Saskatchewan North Battleford Hospital where he is being held and treated, Hamp described how during his relationship with Sanche he was using daily high-potency cannabis with up to 22 per cent THC content from a dispensary.
Months before he killed Sanche, Hamp says, he began having paranoid delusions about secret police he believed were watching them, court records say.
Over four months, there were multiple ER visits and psychiatric appointments during which Hamp says he “downplayed the seriousness” of his delusions and told doctors he was taking his medications, “which was a lie.”
He says the doctors never raised concerns about his cannabis use, but Sanche, court records show, believed that it was contributing to Hamp’s mental health symptoms.
Days before killing Sanche, Hamp claimed in court he had quit cannabis, but his symptoms continued, the documents state.
Sanche made a final call to the Saskatoon Crisis Intervention Service on Feb. 19, 2022.
Just hours after the call with the crisis line concluded, Hamp stabbed Sanche in the apartment they shared.
Sanche died from her wounds on March 16, 2022.
Hamp has his next annual appearance before a review board in late fall 2026, according to his family.
Most people aren’t aware of the increased risk of psychosis among cannabis users, says Michelle West, a University of Colorado researcher and clinician specializing in psychosis in young people.
In more than 40 per cent of the cases where drug use had an impact on the accused’s symptoms, the person started using at or before the age of 15.
West says she has treated children as young as 11. Some already have symptoms of psychosis.
“The evidence is that (cannabis) makes it more likely you’re going to develop psychosis, that it will develop at an earlier age and that you’ll have a worse course of illness and that it will be a barrier to treatment engagement,” West says.
Women as main targets
For months before her mother’s killing, Raquel Almeida Margulies had watched her “best friend,” Ana Paula Kitterhing De Sousa, navigate the drug addiction and aggressive behaviour of her boyfriend, Michael Calvo.
De Sousa was fearful but also felt responsible for Calvo as one of his few close relationships, Margulies said in an interview.
Margulies says Calvo called and messaged her mother incessantly, verbally abusing her and acting erratically while taking drugs.
De Sousa eventually ended her relationship with Calvo, but he continued to contact her.
On Oct. 15, 2024 Calvo called De Sousa several times while Margulies was visiting her mother.
When De Sousa finally answered, Margulies says she could hear Calvo screaming and swearing at her mother until she hung up.
“I looked at my mum and said, ‘Mama, promise me you’re not going to see him anymore.’ She said, ‘I promise,’” says Margulies.
“I left her house at 6:30 p.m. that day. My understanding is that he called and said ‘I’m going to kill myself unless I see you.’ By 10 p.m., she was dead.”
Calvo’s lawyer told the IJB, “Mr. Calvo does not accept the characterization of events (set out by reporters) nor does he wish to provide any further comment or be interviewed.”
Experts say mothers, wives and girlfriends often are forced into the position of advocating for loved ones in mental-health crises, placing them at a heightened risk of being targeted in domestic violence.
The IJB database reveals women and girls account for 46 per cent of victims of homicides committed by people later found not criminally responsible — 73 out of 159. This is almost double the percentage they make up among homicide victims overall.
In 52 out of the 87 cases in which the IJB was able to identify the last person who sought medical help for the accused, that person was a woman.
“We know that in health and other contexts, women frankly aren’t listened to in the same way. It’s frustrating,” says Seto, who consults on NCR cases.
Mothers are especially at risk of being killed by their sons in NCR homicides.
Matricides make up 32 of the 73 female killings in the IJB’s database — the single largest victim demographic for NCR killings overall.
Kevin Webster killed his mother, Moirin, with an axe in her Gibsons, B.C. home where he temporarily resided in December 2020.
More than two years later, a B.C. court found Webster was in the midst of paranoid delusions when he killed his mother. He was declared NCR.
Court documents detail years of failed treatment attempts for Webster’s schizophrenia that forced his mother into the dangerous position of being his caregiver.
In 2019, Webster was admitted to hospital at least seven times for mental health reasons.
Then, three weeks before killing his mother, Webster was involuntarily admitted to a psychiatric ward for six days. He was then released into Moirin’s care.
In the 48 hours before the killing, Webster sought mental health help three times at an emergency room.
“He was unwilling to say why he was there and left without seeing a doctor,” court records state.
Webster’s lawyer did not respond to requests for comment.
During Webster’s NCR hearing, a forensic psychiatrist described Moirin as her son’s “strongest advocate.”
The court heard an extract from a February 2019 letter Moirin had written to her son’s then-community care team, voicing her “greatest concern” that Webster might harm himself or a member of his family when in the throes of his delusions.
“It would not only be tragic, but would be another blow to the stigma and fear associated with poor mental health, schizophrenia most of all,” reads her letter.
“God (forbid) that anyone … should come to any kind of harm.”
‘Revolving door’
Among dozens of failed mental-health interventions captured in the IJB database are hospitalizations that occurred prior to the killing. In these cases, the accused relapsed into psychosis shortly after release from hospital.
Mitchell Arnott stabbed and killed both of his parents, Wayne and Louise, just five days after being released from the psychiatric wing of the Montreal General Hospital.
He had been there for two months after he assaulted his former intimate partner, an act for which he had been found NCR. Before that, Arnott had also been accused of stabbing his former roommate; breach of a bail condition; and a 2021 assault charge involving his father, according to court documents.
“I begged the doctor, explaining that my brother wasn’t ready to be released, but they discharged him anyway,” said Wayne and Louise’s daughter in a victim impact statement.
She described almost a decade of her family being trapped in a “revolving door phenomenon” with hospitals, police and courts.
Over eight years, she watched Arnott being sent to hospital for treatment, then being released after a brief period of lucidity, only to stop taking his medication and be re-admitted. “Over the years, I lost count of the hospitalizations where a doctor promised a different outcome,” reads her statement.
Arnott was also found NCR for the killings of his parents in January 2025.
Contacted through his lawyers and the forensic hospital where he is currently being held and treated, he declined to comment.
As with all individuals whose cases are put under the management of the review board, it is unclear when Arnott will be released.
According to one 2021 study which analyzed all NCR outcomes, including for non-fatal crimes, NCR patients are less likely to be released from detention or supervision compared to offenders convicted in the correctional system.
“Results showed that, on average, NCRMD (not criminally responsible on account of mental disorder) accused received detention dispositions more frequently and had longer periods of detention and supervision than convicted offenders,” the study said.
But Baillie, the psychologist in Calgary, says that in the case of violent offences, he believes absolute discharges should not be permitted.
“In an environment without adequate community support services, it’s either a hospital or nothing and in the nothing cases, you end up with somebody who may be acutely ill who is not being supported,” says Baillie.
A better system, he added, would ensure that even after discharge, “you’re meeting with your psychiatrist regularly and making sure that your medications or other treatment are still effective for you.”
‘Misogyny is misogyny’
The devastation of the NCR decision in her mother’s killing continues to haunt Raquel Almeida Margulies, who says she was blindsided by the outcome.
“I would have loved our shot in court. I would have loved to hear the case, hear all of the evidence,” she says, while adding she believes that “people deserve help” and safe rehabilitation where possible.
But, in her mother’s case, she believes “there’s a pattern that stems beyond any clinical diagnosis, in my opinion.
“Misogyny is misogyny whether or not you are schizophrenic.”
It’s a question many critics have about the NCR system: Can you be sure someone isn’t responsible for their actions and not using mental health as an excuse to avoid jail?
“It’s not easy to convincingly feign psychosis,” says Dr. Sandy Simpson, a senior scientist at the Centre for Addiction and Mental Health (CAMH) in Toronto.
“It’s easy to say ‘Oh, I’m hearing voices and the voices made me do it.’ But those voices come in a context,” he says, adding that assessing a person in multiple ways over a period of time, as well as cross-checking with other information helps test whether their claims have the ring of truth.
“It is possible and very occasionally it (malingering) occurs, but it is very rare.”
Simpson says he doesn’t overall see an upside to someone lying to be declared NCR for any crime because the lie can become a significant barrier to ever being released.
“Occasionally you do get people who say, ‘Well, actually that never happened … I only made it up to get in here,’” he says.
“But that creates an impossible dilemma for the treating staff. So, what do I (the doctor) do? Do I believe the person who’s telling me now ‘I lied back then,’ or how do I tell if they are not lying now? There is no easy way out of that.”
Calvo’s Ontario Review Board documents state that upon arrival at the forensic hospital following Calvo’s NCR finding, he “has shown no symptoms of depression or psychosis … hallucinations, paranoia or delusions of reference, has not required seclusion, and has not been involved in any incidents of violence or aggression.”
They also note, however, that Calvo is in the “early days” of his treatment and that he is accomplished at “masking symptoms and appearing more well than he is.”
In June 2026, eight months after the NCR finding was made, Margulies received a call from the RCMP telling her Calvo had been granted day passes to leave the forensic hospital where he is currently being treated.
Margulies has no idea when Calvo might be fully released, but worries that sometime in future she “could be at my mom’s favourite restaurant and he could be having a beer beside me.”
The handling of the case has left her questioning the justice system.
“There’s this idea that good overcomes evil. When bad things happen, there are consequences. I feel like that very foundational understanding of things was just ripped away from me,” says Margulies.
“I feel like I’m existing in this world of trying to feel safe.”
— With files from Dori Seeman.
The Investigative Journalism Bureau (IJB) at the University of Toronto’s Dalla Lana School of Public Health is a collaborative investigative newsroom supported by Postmedia that partners with academics, researchers and journalists while training the next generation of investigative reporters.
