It has been hot in the fire scene and only on Friday morning could the police start a technical investigation at the preschool. On site are police technicians who also carry a fire dog.

"We'll see what it gives," says Lars Liewenborg, head of the police department for serious crimes in Nyköping.

There has been information that the fire started in containers in connection with the preschool, but that is not entirely clear.

- There is also information about a garbage can in connection with the building and it is not really the same. But it's really too early to comment on the cause of the fire, says Lars Liewenborg.

"The evidence usually burns up"

At present, there are no suspected perpetrators and the police technicians are not expected to be fully clear with their investigation during Friday.

According to Johan Levin, the local police area manager in Nyköping, it is always problematic to investigate fires.

"The evidence is naturally able to burn up," he says.