Flags flew at half-mast across Finland on Wednesday as the country mourned a 12-year-old boy who was shot dead at school, with police saying a fellow sixth-grader was their only suspect.

Two other pupils at Viertola school, both girls also aged 12, were severely wounded in Tuesday’s attack and were undergoing treatment in hospital, the police said in a statement.

“The police have a preliminary understanding of the motive for the act, but for
investigative reasons, it cannot be confirmed yet,” the
police said.

They said the suspect had admitted the shooting during an initial investigation but no one has yet spoken in public on the suspect’s behalf. He was put in the care of social services because a child cannot be remanded in custody.

After word spread of the shooting on Tuesday morning, anxious parents waited for hours outside the school as teachers kept classroom doors shut to protect their pupils while the police searched the buildings.

The suspect was apprehended some 4km away carrying a revolver, police said.

The suspect and the deceased boy were both Finnish citizens, they said. One of the injured girls was also Finnish, while the third victim was a dual citizen of Finland and Kosovo.

Investigators warned people not to spread rumours online.

“There is a lot of different, partly incorrect information about what happened ... The police continue to point out that spreading incorrect information on social media is a crime,” they said.

Following deadly school shootings in 2007 and 2008, Finland tightened its gun legislation in 2010 and introduced an aptitude test for all firearms licence applicants. The minimum age for applicants was also raised from 18 to 20.