Last Monday, a man in his 25s was shot to death at a pedestrian crossing in the district of Brunnsbacken in Eskilstuna.
An intense police search for the killer began.
Two people were arrested for involvement in the act.
They have now been written off, according to chamber prosecutor Maria Lindstedt Estberg.
On Thursday, the suspected teenager, who has now been arrested on probable cause on suspicion of murder, was arrested.
- At the moment, only the 17-year-old is relevant, says Maria Lindstedt Estberg.
Found weapon
In connection with the investigation, the police found a weapon and other goods in a forest grove, approximately 700 meters from the crime scene.
According to the prosecutor, it has been possible to link the 17-year-old to finds in the forest grove through DNA traces, but not yet to the weapon.
Prosecutor Lindstedt Estberg does not want to reveal what the findings are about.
The 17-year-old suspect denies the crime.
Through previous judgments, it can be read that the 17-year-old has a problematic background.
At a school in Eskilstuna, he is said to have attacked another student with violence and destroyed furnishings in his early teens.
Threatened treatment assistants
He has been placed in HVB and SiS homes.
Together with several other young people, the 17-year-old threatened and raped two treatment assistants at a closed SiS residence in Värmland in April last year.
The young people came across keys, access cards and telephones and escaped from the accommodation.
The 17-year-old was convicted of grossly arbitrary conduct and violence against an official.
The penalty: youth care.