The 23-year-old suspect, a Finnish man, admitted to the Thursday violence and said he did not know the victims and did not choose them for any particular reason, police added.
There was “no reason to suspect that the act was motivated by terrorism or racism”, said police, noting the man had a record of violent crime.
The suspect told investigators that “all humans are enemies” and that “everyone is stalking him”, Detective Chief Inspector Sakari Tuominen told reporters on Friday.
The suspect also said that “people get what they ask for” and that “he wanted to end his own suffering with this act”.
“The motive will be clarified during the preliminary investigation through interviews,” Tuominen said.
Police were alerted to the stabbing outside a shopping centre in central Tampere at 4.23pm (9.23pm, Singapore time) on Thursday.
The victims received first aid at the scene and were now receiving hospital care for “severe injuries”, according to police, though none of the victims had life-threatening injuries.