Sten Fransson

Sten Adolf Reinhold Fransson (11 May 1934 – 29 September 2012) was a Swedish man notorious for committing multiple murders, including a triple killing in 1975 — an incident that later became known in Sweden as the Vattnäs Drama (Swedish: Vattnäsdramat) — and the murder of his wife in 2012. Born in Strömsund, Jämtland County, Sweden, Fransson came from a large family and began his military career around 1950 at the Bergslagen Artillery Regiment in Kristinehamn. Colleagues described him as socially withdrawn, emotionally unstable, and prone to a volatile temper. He married young and had children, but that marriage ended in divorce. During the 1970s, he struggled with alcohol abuse and emotional instability.

While serving as a warrant officer, Fransson began a relationship with Gunilla Persson, a folk musician from Vattnäs, Dalarna. Their relationship was troubled, particularly with Gunilla's mother, Hilma. On Christmas Eve 1975, Fransson visited Gunilla's family. After arguments escalated, he retrieved his service pistol and shot Gunilla, her parents Anders and Hilma Persson, and Gunilla's 10-year-old daughter Anette. Gunilla and her parents were killed, while Anette survived but suffered permanent spinal injuries. Fransson attempted suicide, but his gun was empty, and he called for help. He was arrested without resistance.

During his trial, Fransson admitted the killings but had little memory of the events. Psychiatric evaluation determined he acted under severe mental disorder, and he was sentenced to compulsory forensic psychiatric care at Säter Hospital. After approximately nine months, he was declared mentally fit and released, a decision that later drew criticism. He reunited with his former wife, remarried, and worked in administrative positions within the Armed Forces. The 1975 murders prompted national debate in Sweden over the regulations allowing military personnel to carry service weapons off duty.

On 13 August 2012, Fransson fatally stabbed his wife Ulla-Britt in their Kristinehamn apartment and attempted to harm himself. Investigators cited jealousy, emerging dementia, and possible medication influence as factors. He died of a heart attack on 29 September 2012 before the case could go to trial.