ZURICH, May 29 (Reuters) - Swiss federal prosecutors have taken over the investigation into Thursday's knife attack at Winterthur railway station and are treating the case as suspected terrorism, the Office of the Attorney General (OAG) said on Friday.
The federal prosecutor said it had opened criminal proceedings against the suspected attacker on suspicion of multiple attempted murder and participation in, or support for, a terrorist organisation.
Three Swiss men were injured in the attack which took place on Thursday morning in Winterthur, a city to the north of Zurich.
One person was stabbed in the leg, another in the neck, while a third man was stabbed in the thigh. All were taken to hospital with the third man needing emergency surgery for his injuries.
Police arrested the alleged perpetrator, a 31-year-old dual Swiss-Turkish national, at the station a few minutes after the first emergency call was received.
Investigators are now focusing on the motive for the attack, including a detailed review of the suspect's background.
The prosecutor's office said its "main hypothesis" was that the attack was suspected terrorism.
The suspect had previously been reported to the police in 2015 for spreading propaganda from the hardline militant group Islamic State, police said on Thursday.
Swiss newspaper Blick also said it had obtained a video showing a man running out of the concourse of Winterthur station shouting "Allahu Akbar", an Arabic phrase that translates as "God is greatest". Reuters did not independently verify the video.
The federal prosecutor on Friday said the incident showed jihadist-motivated terrorism remained a serious concern in Switzerland.
(Reporting by John Revill; Editing by Aidan Lewis)
