Matti Juhani Saari was born on 20 May 1986 in Finland and spent his early years in North Ostrobothnia. His childhood was marked by recurring health problems, including slow physical development and frequent illnesses. Family members and acquaintances later described him as shy, sensitive, and socially withdrawn. A significant personal loss occurred during his adolescence when his brother died while Saari was still a teenager, an event that reportedly had a lasting emotional impact on him.

During his school years, Saari experienced bullying, which contributed to anxiety and difficulties integrating socially. He eventually dropped out of secondary school before later continuing his education through alternative pathways. He was described as quiet and isolated, with limited social connections. In his late teens and early twenties, Saari reportedly struggled with panic attacks, depressive symptoms, and increasing social withdrawal.

In 2006, Saari entered mandatory military service in the Finnish Army. His service ended after approximately one month when he was expelled for violating orders by opening fire during a woodland exercise. Fellow conscripts described him as silent and difficult to engage with, and he reportedly struggled to adapt to the military environment.

Saari later enrolled in a Hospitality Management undergraduate program at the Kauhajoki School of Hospitality, part of Seinäjoki University of Applied Sciences, located in Kauhajoki. He was a second‑year student at the time of the attack and lived locally while attending school.

In the years leading up to 2008, Saari developed a pronounced fixation on firearms and mass shootings. Friends later reported that he expressed admiration for previous school shooters, particularly incidents in the United States and Finland. He maintained online profiles where he shared videos of himself firing a handgun at a shooting range and collected violent imagery and material related to school shootings. Despite these behaviors, Saari did not have a prior criminal record, although he had been arrested for driving under the influence and reportedly abused alcohol.

In the months before the shooting, Saari was seeing a psychologist. Friends noticed a marked change in his demeanor approximately two years prior to the attack, including increased aggression, obsession with weapons, and fascination with mass violence.

Matti Juhani Saari was born on 20 May 1986 in Finland and spent his early years in North Ostrobothnia. His childhood was marked by recurring health problems, including slow physical development and frequent illnesses. Family members and acquaintances later described him as shy, sensitive, and socially withdrawn. A significant personal loss occurred during his adolescence when his brother died while Saari was still a teenager, an event that reportedly had a lasting emotional impact on him.

During his school years, Saari experienced bullying, which contributed to anxiety and difficulties integrating socially. He eventually dropped out of secondary school before later continuing his education through alternative pathways. He was described as quiet and isolated, with limited social connections. In his late teens and early twenties, Saari reportedly struggled with panic attacks, depressive symptoms, and increasing social withdrawal.

In 2006, Saari entered mandatory military service in the Finnish Army. His service ended after approximately one month when he was expelled for violating orders by opening fire during a woodland exercise. Fellow conscripts described him as silent and difficult to engage with, and he reportedly struggled to adapt to the military environment.

Saari later enrolled in a Hospitality Management undergraduate program at the Kauhajoki School of Hospitality, part of Seinäjoki University of Applied Sciences, located in Kauhajoki. He was a second‑year student at the time of the attack and lived locally while attending school.

In the years leading up to 2008, Saari developed a pronounced fixation on firearms and mass shootings. Friends later reported that he expressed admiration for previous school shooters, particularly incidents in the United States and Finland. He maintained online profiles where he shared videos of himself firing a handgun at a shooting range and collected violent imagery and material related to school shootings. Despite these behaviors, Saari did not have a prior criminal record, although he had been arrested for driving under the influence and reportedly abused alcohol.

In the months before the shooting, Saari was seeing a psychologist. Friends noticed a marked change in his demeanor approximately two years prior to the attack, including increased aggression, obsession with weapons, and fascination with mass violence.

Saari left behind two handwritten notes in his dormitory room stating that he had been planning the attack for approximately six years and expressing hatred toward humanity as a whole. Investigators stated that the notes reflected deep psychological distress but did not indicate a specific ideological or political motive.

Finnish police confirmed that Saari had legally obtained his firearm in August 2008 using a temporary permit. An anonymous tip had alerted police to Saari’s online videos days before the shooting, prompting officers to question him and search his residence on 22 September 2008. At that time, no legal grounds were found to detain him. After the attack, a police inspector involved in the case was charged with dereliction of duty, though broader investigations found no evidence of direct coordination with other shooters.

Authorities examined possible copycat influence from the 2007 Jokela school shooting. While no personal contact was found between Saari and the Jokela gunman, investigators concluded that Saari had been influenced by previous school shootings and had deliberately modeled aspects of his behavior and appearance on them.

The Kauhajoki shooting was the deadliest peacetime attack in Finnish history at the time and the second school shooting in Finland within one year. A national day of mourning was declared, and the incident prompted sweeping changes to Finnish gun legislation, including stricter handgun licensing and enhanced monitoring of online threats.

The attack remains a defining event in Finland’s modern history and continues to shape discussions on mental health services, gun control, and early intervention in cases of violent ideation.