Finland’s worst female serial killer is, of all people, a nurse, whose job is to look after the well-being of patients. But this was not the case with nurse Aino Nykopp-Koski, who preferred to poison her elderly and bedridden patients with medication. The killer nurse, who, after marrying a man 20 years her junior whilst in prison, took the name Ann Maria Gyllgren, was born in November 1950 in Rantsila, Finland, and has gone down in the annals of criminal history as one of the country’s most notorious female serial killers. Her story begins in a professional setting that demands trust and empathy: nursing. Whilst working as a nurse between 2004 and 2009, she committed five murders and five attempted murders of patients. Her alleged motive remains unclear, but the dark shadow of greed and manipulation looms large, as Aino often stole from the victims she poisoned. Aino grew up at a time when the healthcare system in Finland was undergoing major changes. After qualifying as a nurse, she began working in various institutions where she was responsible for the care of elderly patients, many of whom were in need of assistance. Even before the murders, Aino had been convicted of stealing narcotics and her patients’ property and had already served a suspended sentence. The first three identified victims died in hospital between 2004 and 2006, though the cause of death initially remained undetermined. It was not until years later that a forensic chemical analysis revealed that, in two cases, the cause of death was an overdose of a drug that affects the central nervous system. A turning point came in the spring of 2009. A witness reported that Aino had mixed life-threatening medication into a yoghurt, leading to another case of poisoning. Furthermore, a patient who had been admitted to hospital with life-threatening symptoms claimed that she had been poisoned by Aino. This fatal combination led the police to launch a full-scale investigation into her. During this investigation, numerous similar cases of poisoning were uncovered. A disturbing pattern began to emerge. Aino had even poisoned a colleague by mixing eye drops into her coffee. Furthermore, the police seized over 1,800 tablets from Aino. On 14 May 2010, Aino was found guilty in a preliminary verdict of five murders and five attempted murders. The judicial investigation found that she had acted whilst fully conscious and suffered from an antisocial personality disorder with psychopathic traits. She was able to manipulate others through feigned empathy, which makes her actions seem all the more abhorrent. On 22 December 2010, the Helsinki District Court sentenced her to life imprisonment. Despite the overwhelming evidence and the psychiatric reports confirming her guilt, Aino continued to maintain her innocence. The case caused a huge stir in Finland and was regarded by the media as one of the most serious murder cases in modern Finnish history. The term ‘Poison Nurse’ quickly became synonymous with Aino, who had abused her patients’ trust. Public debate began to flourish regarding the psychological aspects of her actions and the structural weaknesses in the healthcare system that had enabled her to commit murder. In 2020, Aino applied for early release after eleven years in prison; however, her application was rejected due to her numerous crimes and the likelihood of her reoffending. A further application in 2022, following a name change to Gyllgren, was also unsuccessful. In 2023, Gyllgren again applied for her sentence to be quashed, as she continues to vehemently insist that she is innocent. The case is making its way through the courts. Until a final decision is reached, the public and the media are expected to continue to follow closely how this complex case will unfold. The case of Ann Maria Gyllgren is both a tragedy and a chilling reminder of how the trust placed in healthcare professionals can be exploited. Gyllgren’s ability to commit murders over a period of years whilst working as a nurse raises fundamental questions about ethical standards within the healthcare sector. Her story is far from over, and whilst Gyllgren continues to fight for her freedom, society remains called upon to learn from this grim chapter.



