The boy was lifeless when he was found and later pronounced dead at the hospital.
The police have been tight-lipped about what happened and are currently working to secure leads, knock on doors and find out what happened.
A police source tells SVT that "the crime came like a bolt from the blue" for the police.
The boy should not be known to the police from before, according to the source they were caught off guard by what has happened.
Sandvikens IF in mourning
The boy was active in Sandvikens IF.
The club writes on social media that it is in mourning and that one of their youth players is the boy who was shot to death on Tuesday evening in Sandviken.
"We have received the tragic news that a youth player in our association was killed in an accident yesterday.
Sandvikens IF's thoughts go out to the family and those closest to them in this moment of unreal grief".
On Wednesday evening, the association invited teammates, leaders and parents to meet, socialize and talk.
The article is updated.
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Police on site at the cycle path where the shot teenage boy was found - Hear SVT's reporter about the shooting.
Photo: Stefan Larsson/SVT