Finland's news agency says the Moroccan asylum-seeker who killed two people and injured eight others in a stabbing attack in August is not part of a wider extremist group and likely acted alone.

Police detained three other people on suspicion of helping plan the Aug. 18 knife attack in the southwestern city of Turku, but they have been released one by one.

The STT agency quoted investigator Olli Toyras as saying Tuesday that police had concluded "there are no indications" the Turku stabber was part of a wider group but he may still have received outside help.

The suspect has been identified as Abderrahman Bouanane, 22, and the attack is being investigated as murder with possible terrorist intent. He has acknowledged the stabbings but denies that those deaths were murders.