A hospital can be audited by the number of its doctors in the corridor. A care home or a client’s front room cannot. The work is done at night or alone, by people on modest wages, for residents who are often too frail or too confused to describe what is happening to them, and whose deaths are expected. Five cases from Canada, the United States, Finland, Norway and Switzerland show the same arrangement of trust and invisibility, and five different ways of discovering that it had been abused.
Elizabeth Wettlaufer was a registered nurse in Ontario from 1995 to 2016. Between 2007 and 2016 she gave insulin overdoses to fourteen people in her care, most of them elderly residents of long-term care homes in Woodstock, London and Paris. Eight died. On June 1, 2017, she pleaded guilty in Woodstock to eight counts of first-degree murder, four of attempted murder and two of aggravated assault. On June 26 she was sentenced to life with no eligibility for parole for twenty-five years.
She had a history before she ever reached a ward. In 1995, in her first nursing job, she collapsed at work after taking a controlled drug from the supply, and was fired and reported to the College of Nurses of Ontario, which put conditions on her licence; they were lifted in 1998. For most of the following decade she worked as a support worker. In June 2007 she was hired as a registered nurse at a long-term care home in Woodstock, with only that support work as her reference. Within weeks she began to harm residents. In August 2007 she killed the first of them, James Silcox, 84, a Second World War veteran and father of six, according to the facts read in court.
The access was ordinary. The nurse on a shift controlled the medication, and insulin, she told inquiry lawyers, was not closely tracked where she worked, unlike narcotics. Residents were old, many had dementia, and deaths drew no questions. A pathologist told the later inquiry that autopsies would probably not have revealed intentional insulin overdoses anyway. Her employers saw something else: a nurse who made medication errors. The home disciplined her several times, and in March 2014 it ended her employment. It filed a termination report with the College on April 17, 2014, gave her a reference and a settlement of $2,000, and the College decided no investigation was needed. By April 22 she was working at a care home in London, where in August 2014 she killed Arpad Horvath, 75. From January 2015 she worked through a nursing agency, and in July 2016 she took a job with a home care provider in Oxford County. In August 2016 she tried to kill a woman in her care in Ingersoll, the one offense outside a licensed care home.
What stopped her was fear, not detection. Told she would soon be reassigned to children with diabetes, she did not trust herself to control her impulses. She quit her jobs and on September 16, 2016 checked herself into the Centre for Addiction and Mental Health in Toronto, where she told her psychiatrist what she had done and wrote out a four-page confession from memory. Over nine years she had already told others. According to the agreed facts reported by The Canadian Press, a former girlfriend threatened to report her if she did it again. A pastor and his wife prayed with her and said they would go to the police if she killed again. In 2014 a criminal lawyer advised her that it was in her interest to stay silent and seek help. Nobody went to the police.
Commissioner Eileen Gillese released a four-volume, 1,500-page inquiry report in Woodstock on July 31, 2019. She wrote that the offenses would not have been discovered without the confession and that they resulted from systemic vulnerabilities, not from individual or organizational misconduct, so she made no findings of misconduct against anyone. She listed medication management, staffing levels, agency nurses, oversight of home care and the way deaths were reported. She made 91 recommendations, among them an electronic death record so that clusters of deaths could be tracked. "It is not possible to detect or deter something unless you are aware it exists," she said. Wettlaufer’s nursing registration had been revoked on July 25, 2017.
The deaths at a nursing home in Walker, Michigan, a suburb of Grand Rapids, were put down to natural causes in early 1987. No autopsies were done. More than a year later the former husband of Catherine Wood, who had supervised nurse’s aides there, went to police with what she had told him: that she and a co-worker, Gwendolyn Graham, had killed patients. His account was an allegation passed on by a witness, and the court did not find a motive.
Graham, then 25, was in Texas. She was held on a $1 million bond from early December 1988, fought extradition for about six weeks and in January 1989 agreed to return. Police first spoke of as many as eight patients; charges were brought in five deaths only. Before the trial Wood pleaded guilty before Kent County Circuit Judge Robert Benson to second-degree murder and conspiracy to commit second-degree murder, and agreed to testify. She told the jury in September 1989 that Graham had done the killing while she kept watch or drew supervisors away, and that she went along because she wanted to keep Graham as a partner and was afraid of her. A medical examiner who studied two of the women years after their deaths could neither confirm nor rule out the prosecution’s account. Graham testified that no one had been killed and that the two had made the story up.
The jury convicted Graham of five counts of first-degree murder and one of conspiracy. Michigan law made the sentence life without parole. Wood, then 27, was sentenced to 20 to 40 years. Judge Benson told her that without her cooperation the case would never have been cleared up.
The outcome stayed disputed. Wood was refused parole eight times and approved on the ninth, in 2018. The families appealed, Michigan’s Attorney General, Dana Nessel, filed a brief in May 2019 saying that the board had "repeatedly" found Wood a threat, and a retired detective, Tom Freeman, said her testimony had been essential and she had served her time, while his former partner, retired Sergeant Roger Kaliniak, told a Charlotte station in 2020 that he believed she was the mastermind. In October 2019 Kent County Circuit Judge Joe Rossi ruled that the board had not abused its discretion. Wood left a federal prison in Tallahassee on January 16, 2020, and moved to her sister’s house in Fort Mill, South Carolina, under a ban on caring for the elderly, children or vulnerable adults. In May 2026 a Grand Rapids station reported that Graham was seeking clemency and claiming innocence.
Aino Nykopp-Koski was a practical nurse and home care worker in Helsinki, born in 1950, according to Yle. She worked in two hospitals, a care home and home care visits over the years covered by the convictions. In December 2010 the Helsinki District Court convicted her of murdering five elderly patients and attempting to murder five more between 2004 and 2009, and sentenced her to life. The court held that she had secretly given them medicines, mostly sedatives, that no doctor had prescribed. Yle called it the largest murder trial in Finnish legal history, and in 2025 described her case as the only exposed series of killings within the Finnish health care system.
The warning signs were there early. Yle’s 2025 account, drawing on the court record, said that in 2003 and 2004, while she worked on a ward at a Helsinki eye clinic, the hospital district’s head of security learned of thefts from patients and of unexplained sudden turns for the worse after surgery. The matter was not reported to the police. In the years that followed, the five murder victims were a woman of 80 recovering from routine surgery in 2004, a man of 70 with Alzheimer’s disease in 2005, a woman of 85 in home care in 2006, a woman of 90 in home care in 2008 and a woman of 77 with a mental illness in a care home in February 2009. Finnish courts and the press did not publish their names.
At one care home, more than ten residents died within a couple of months while she worked there. Only one of those deaths could be investigated, Yle reported; the others had been cremated before anyone suspected a crime. That one was proved to be murder, and no charge was brought over the rest. The criminologist Martti Lehti, quoted by Yle, said Finland’s otherwise effective system of death investigation had a gap where this kind of crime was concerned.
The case came to light through her own call. At 12:31 p.m. on March 14, 2009, she rang the Helsinki emergency center to report that a home care client had collapsed. The woman recovered, tests showed sedatives she had not taken herself, and she told doctors she suspected her carer. It took her until the fourth day to convince one. Police began their inquiry that month and arrested the nurse. At the appeal the state prosecutor, Leena Metsäpelto, said the defendant had given patients lethal medicines and then called the emergency services, often the relatives too, apparently to keep suspicion away from herself. "She had a pattern that she followed," she said.
Psychiatrists examined her before the verdict and the court held her criminally responsible; no motive was identified. She has denied every charge, at trial, on appeal and in later hearings. The Helsinki Court of Appeal upheld the sentence on March 29, 2012. By 2025 she was known in the courts as Ann Maria Gyllgren. The court refused her release in 2020, in 2022 and on May 13, 2025, and she applied for the fourth time in June 2026.
Arnfinn Nesset was a trained nurse who in 1976 became manager of the nursing and old people’s home in Orkdal, near Trondheim. In March 1983 a jury at Frostating lagmannsrett, sitting in Trondheim, convicted him of 22 murders and one attempted murder of residents, and of taking money from patients. It acquitted him on two further murder counts. United Press International called it Scandinavia’s biggest peacetime mass murder case. The residents who died between May 1977 and November 1980 were aged 67 to 95, according to UPI; their names did not appear in the reports.
His position gave him the means. In 1977 he obtained Curacit, a muscle relaxant used in surgery, for a home where, as Adresseavisen wrote in 2002, such a drug had no place. Staff began to talk about the sudden deaths the same year. The paper said there were few clear signs, and the suspicion hung over the home for about three more years without anyone in authority looking into it. In late autumn 1980 it emerged that he had altered a pharmacy prescription and ordered Curacit in large quantities, saying it was for putting down a dog. The county physician and the police were told, and UPI credited a local journalist with finding that large quantities had been sent to the home. He was arrested in January 1981.
The case rested on his words. During the investigation he confessed, over nearly a thousand hours of questioning according to NRK, to between 27 and 31 killings, depending on the report. Police considered opening graves in Orkdal to test the dead but did not, because he had confessed; UPI wrote that the bodies had been cremated. Shortly before the trial he withdrew every confession. NRK reported that the prosecution case rested on what witnesses had seen and on the interrogation record; UPI listed the confession, the existence of the poison and the testimony of witnesses. The trial lasted five months and heard 128 witnesses. He was sentenced to 21 years, the maximum under Norwegian law, with 10 years of preventive detention. The question of motive was never settled; the presiding judge spoke of wanting to help the patients "over the last hill."
He was moved to supervised release in 1993 and freed in 2004, and lived under another name. In 2024, at 87, he gave his first press interview and said he wanted the case examined again. In autumn 2025 the journalist Simen Sætre published a book arguing that several confessions were probably false. Nesset died in a nursing home in December 2025, aged 89. His lawyer confirmed it on December 3. No court had looked at the case again.
Roger Andermatt was a nurse in central Switzerland. He was arrested in Lucerne at the end of June 2001 after a suspicious death at the nursing home where he worked, and first admitted killing nine patients there, all elderly women, with the deaths dating from December 2000. The Associated Press reported that he said he had acted out of pity. Investigators extended the inquiry to the other homes where he had worked, and under questioning he confessed to 18 more killings, 12 of them at a home in Sarnen, the main town of Obwalden. On September 11, 2001 the investigating magistrate, Orvo Nieminen, told a news conference in Lucerne that the figure was 27 over six years, by overdoses or smothering, in some cases after sedation. The agency wrote that it appeared to be the worst series of killings in Swiss history.
His working life had been spent in care. Before training as a nurse, Blick reported, he worked at a home for elderly people in Sarnen and for the home nursing service; he later returned as deputy to the ward sister. A former colleague who spoke to Blick on condition of anonymity said he cared only for women, at his own request, that his favorite shift was the night shift, and that when the team discussed active euthanasia his position was the most extreme in the room: "Why not?" Many people died in the Sarnen home at that time, she said.
He described mercy. The magistrate said he had consistently given his motives as sympathy, compassion and a wish to end suffering, and he conceded that in some cases he was simply overwhelmed by the stress of the work. He was sentenced to life imprisonment. The date and court of the conviction have not been reported. In May 2016 Blick wrote that he had killed 22 people between 1995 and 2001, fewer than the 27 he had confessed to, and called him the Swiss serial killer with the most victims. The gap between the two numbers is the usual one in such cases: what a man says, and what a court is prepared to hold.
The jobs gave the same thing. A night shift with a small staff, a cabinet or a cart the person on duty could open, residents whose deaths needed no explanation, and in four of the five cases a drug that most inspectors, coroners and colleagues never connected to a crime. In Helsinki the opportunity extended to home care visits, and in Ontario to a woman served by a home care provider. None of the five was caught by a system built to catch them.
How each was noticed varies. Wettlaufer reported herself, after nine years and several people who knew. The Michigan women came to light through a former husband’s report. Nesset’s case began with a journalist and a pharmacy prescription. Nykopp-Koski was reported by a client who survived, after a call she made herself. Andermatt was arrested after one suspicious death. In each case the first person to say something was not a regulator or a coroner.
Courts then split on how much to rely on what the accused had said. Norway convicted on confessions later retracted, and a book and an old man’s request to reopen the case arrived too late for the court. Switzerland’s totals, in public at least, rest on confessions. Finland and Michigan convicted on contested evidence and on an accomplice. Canada had a guilty plea and used the public inquiry for the questions the plea could not answer, and its commissioner found a strained but not broken system and no one to blame. Parole is where the stories have not ended: Wood is out, Graham is asking for clemency, and Nykopp-Koski has been refused three times and is asking again.
• 1977: Nesset obtains a muscle relaxant for the nursing home he manages in Orkdal, Norway; staff begin to talk about sudden deaths.
• 1980 (late autumn): It emerges that Nesset had altered a pharmacy prescription and ordered the drug in large quantities.
• 1981 (January): Nesset arrested.
• 1983 (March): Nesset convicted of 22 murders and one attempted murder; sentenced to 21 years plus 10 years of preventive detention.
• 1987: Five elderly women die at a nursing home in Walker, Michigan; the deaths are recorded as natural.
• 1988 (December): Gwendolyn Graham held in Texas on a $1 million bond.
• 1989 (September): Graham convicted of five counts of first-degree murder; Wood sentenced in October to 20 to 40 years.
• 1995 to 2001: Roger Andermatt’s killings in Swiss care homes, by a 2016 newspaper count.
• 2001 (June and September): Andermatt arrested in Lucerne; on September 11 the magistrate announces 27 confessed killings.
• 2004: Nesset released.
• 2004 to 2009: Aino Nykopp-Koski’s five proved murders in Helsinki.
• 2007 (August) to 2016: Elizabeth Wettlaufer harms 14 people in Ontario care settings.
• 2009 (March 14): Nykopp-Koski’s emergency call; she is arrested that month.
• 2010 (December): Nykopp-Koski sentenced to life.
• 2012 (March 29): Her sentence is upheld.
• 2016 (September 16): Wettlaufer checks herself into a Toronto hospital and confesses.
• 2017 (June 26): Wettlaufer sentenced to life with no parole eligibility for 25 years.
• 2019 (July 31): Ontario inquiry report released with 91 recommendations.
• 2019 (October): A Michigan judge rules Wood’s parole may stand; she is released January 16, 2020.
• 2025 (May 13): Nykopp-Koski’s third parole application refused.
• 2025 (December 3): Nesset’s death confirmed by his lawyer.
• 2026 (June): Nykopp-Koski files a fourth parole application.