A pattern across care settings
Aino Nykopp-Koski, later known under other names and currently as Ann Maria Gyllgren, worked as a practical and home-care nurse in Helsinki. Finnish courts concluded that between 2004 and 2009 she deliberately gave elderly people medication that was inappropriate for their treatment or in dangerous quantities.
The victims were largely patients whose age and health left them unable to protect themselves. The case eventually became one of the largest serial-murder prosecutions in modern Finnish legal history.
Investigation and prosecution
Nykopp was detained in March 2009. Investigators examined deaths and medical incidents connected with facilities and people she had cared for. Because some patients had already been cremated before criminal suspicions emerged, not every suspicious death could be tested or proved in court.
Prosecutors nevertheless assembled a case covering multiple victims and attempted killings. The evidence centered on medication, the circumstances in which patients became critically ill, and the recurring connection to Nykopp's work.
Five murders and five attempted murders
On 22 December 2010, Helsinki District Court convicted Nykopp of five murders and five attempted murders and imposed a life sentence. The judgment also covered other offenses. The court found that she understood the consequences of her actions and was criminally responsible.
Nykopp denied the charges and appealed. The Helsinki Court of Appeal upheld the life sentence in 2012, and the Supreme Court later refused leave to appeal, leaving the conviction final.
Release applications and current status
The case has continued to return to the courts through applications for conditional release. In May 2025, the Helsinki Court of Appeal rejected another application, emphasizing the seriousness and number of the offenses and information concerning the risk of reoffending.
In June 2026, Yle reported that Gyllgren had submitted a fourth application for release. At that time she had spent about 17 years in custody and prison. She continued to deny committing the murders. The filing did not overturn or weaken the final convictions; it concerned whether and when a person serving a Finnish life sentence could be conditionally released.
Why the case matters
The Nykopp case exposed the particular difficulty of detecting homicide when victims are elderly, medically fragile and receiving numerous legitimate medications. It also raised questions about medication control, institutional oversight and how suspicious clinical events are recognized when they occur across different workplaces.
The criminal record is unusually extensive, but the central fact remains the loss and harm suffered by patients entrusted to professional care. This archive uses the nickname associated with the case only for identification and searchability, not as a sensational label.