On 18 August 2017, a mass stabbing took place in Turku, Finland. Two people were killed and eight others were injured before the perpetrator, 22-year-old Abderrahman Bouanane, was detained. In June 2018, he was found guilty of two counts of murder with terrorist intent and eight counts of attempted murder with terrorist intent, receiving a sentence of life imprisonment.
Boaunane, a Moroccan rejected asylum seeker, had been using the alias Abderrahman Mechkah, which was later discovered to be a false identity. Bouanane reportedly identified as a soldier of the Islamic State (ISIS). He had been radicalised three months before the stabbing took place. During the investigation, ISIS propaganda material and a video of him reciting a manifesto was discovered among his possessions. The attack was the first Islamic terrorist act in Finland as well as the first crime in the country to be legally classified as a terrorist incident.
Finland had not experienced terrorist attacks and had faced very little political violence since the end of World War II.
In June 2017, the Finnish Security Intelligence Service assessed the overall terrorist threat as level two ("elevated") on its four-tier scale. According to the Service, the most significant terrorist threat in Finland was at the time "posed by individual actors or small groups motivated by radical Islamist propaganda or terrorist organisations encouraging them." Europol's assessment of terrorism threats in the European Union (EU) in 2016 was similar to that of the Service:The terrorist threat in the EU in 2016 emanated from remotely directed individuals operating alone or in small groups, and those that may have been inspired by terrorist propaganda, but not directed. The former are receiving direction and personal instruction from, and are possibly being facilitated by, a terrorist organisation. The latter are individual attackers, possibly but not necessarily being helped by family and/or friends as accomplices. They are inspired by jihadist propaganda and messaging, but not necessarily receiving personal direction or instruction from any group.
Between 1 January 2015 and 31 March 2017, Finland received 39,000 asylum applications.
Bouanane arrived in Finland at the beginning of 2016. He had previously lived as an illegal alien in Germany, residing in various cities in North Rhine-Westphalia and using several different identities from the end of 2015 until early 2016 without seeking asylum. He was arrested twice on assault charges in Neuss and Kerpen, and noted by immigration authorities in Hamburg for his unauthorized presence in the country. He had no prior convictions in Finland according to the Finnish Legal Register Centre, but the Finnish Security Intelligence Service confirmed receiving, in early 2017, a non-specific tip-off that Bouanane appeared to be becoming radicalised and was interested in extremist ideology. The tip-off did not contain information suggesting an actual attack. His asylum application had been rejected, which he was in the process of appealing.
According to persons interviewed at the Pansio asylum-seeker reception centre by national broadcaster Yle, Abderrahman Bouanane arrived at the centre in December 2016 and displayed radicalist behaviour during his stay, such as asking how he could join the Islamic State of Iraq and Syria (ISIS), listening to radicalist sermons on his phone and considering Finns to be infidels (kuffār). The interviewees warned the reception centre management of the behaviour in January 2017. Helsingin Sanomat published similar interviews afterward.
Yle also reported that the police were at the time monitoring approximately 100 young asylum seeker men in the Southwest Finland area and that police believed Bouanane had radicalized fairly quickly during August; for example, his behaviour and clothing style had changed. Bouanane was not one of the 350 individuals monitored by the Finnish Security Intelligence Service for terrorism-prevention purposes.
According to concluding remarks by the Finnish National Bureau of Investigation (NBI) after the case was closed, Bouanane told during his interrogations that he started having an interest in ISIS propaganda three months prior to the attack. Police believed he was a lone wolf and there was no evidence of direct contact between any terrorist organization and him. Bouanane possessed ISIS material, such as photos and videos, on his mobile phone and his computer; his close friends believed he displayed signs of radicalization. Bouanane saw himself as a soldier of ISIS and said one motive for his attack were airstrikes by the Western coalition during the 2017 Battle of Raqqa in Syria. According to NBI, his vision was to die in the attack as a martyr similarly to previous attacks in Europe that he admired. He hoped that ISIS would claim his attack—although this did not happen.
Around noon of 18 August 2017, Abderrahman Bouanane took two kitchen knives with him and cycled from a friend's place in Kaarina to downtown Turku, where he attended a Muslim prayer at a mosque next to the river Aura. From there, he proceeded to a park outside Turku Cathedral and read a manifesto he had drafted on video. The manifesto was religiously inspired and contained, among others, discussion on the infidelity of Western nations as well as how oppressed Muslims should act. Bouanane disseminated the video to a group chat on an instant messaging service. Next, he moved to the local bus station where he intended to attack a military conscript, believing a soldier to be a valid target. Bouanane cancelled after other people arrived at the scene and he moved to Turku Market Square.
At around 16:02, Bouanane, armed with the two knives, stabbed four people at the west corner of Market Square. The Emergency Response Centre alerted all nearby police patrols to the incident. Bouanane stabbed six more people while yelling "Allahu akbar" and running towards Puutori, approximately 465 metres (1,526 ft) away. When police confronted Bouanane stabbing a victim at street address Brahenkatu 14 near Puutori, he ignored verbal orders and was immobilised with a single shot to the thigh and a taser at 16:05. He was given first aid and taken into custody.
Two people died as a result of the attack: one at the scene of the incident, and another in hospital. Eight victims were non-fatally wounded, six of whom were women and two men; three of them were critically injured. One of the victims was aged 15, the others were adults. Both of the fatalities were Finnish women, born in 1951 and 1986. Among the wounded there were a British man, an Italian woman, a Swedish man, and a 15-year-old Syrian girl who arrived in Finland as an asylum seeker. The Italian citizen did not receive critical injuries while the British citizen, Hassan Zubier, who was a paramedic living in Sweden, was injured four times as he tried to help a victim. Zubier, hailed as a hero by Finnish media, was open about the incident and appeared on national television to discuss it. He stated that after he had rushed to treat a bleeding woman injured during the attack, Bouanane stabbed him several times. Zubier suffered a severed spinal cord and severe nerve damage and lost his mobility. He was critical of some by-standers who took photos and videos of the scene instead of helping and partly blamed the media for this kind of behaviour. He was awarded the George Medal for his bravery.
The police suspected early on that the attacker had purposely chosen females as his victims, as the male victims were injured while trying to help other victims or stop the attacker. It was later discovered that the attacker had previously planned attacks at different sites, which would have included male casualties. Thus, police no longer had reason to believe that the casualties were picked based on their sex.
Turku City Library and Hansa shopping centre were evacuated, and police initially advised people to avoid the city centre area. Finnish Prime Minister Juha Sipilä tweeted on 18 August 2017, at 17:09: "The Government is closely following the events in Turku and the on-going police operation. The Government will meet later today." Finnish police increased security across the whole nation, such as at Helsinki Airport and Helsinki Central railway station along with other transport hubs across Finland. A crisis service hotline and an on-site crisis service point were established in the Turku area and the number of on-call social workers was doubled. Flags were flown half-mast on 19 August and a national moment of silence was held at the Market Square on 20 August.