There is no suspicion against any physical person, but the decision to initiate an investigation with a crime classification is about getting the resources needed to investigate the accident, according to the police.
It was on Saturday that the boy was found lifeless in a pool at Skara summerland. A lifeguard picked up the boy and started heart-lung resuscitation until the ambulance arrived.
The boy was taken to the hospital, but his life could not be saved.
Over the weekend and on Monday, the police have held several interrogations.
We need to gather information, and we do that primarily by holding interrogations to create as clear a picture as possible of what happened on site, says Marcus Åblad, group leader at the police in Skaraborg, to TT.
He does not want to give any more details about the accident, or what may be the background to it.