The detained person is a man in his 25s from Gävle and was arrested during the night. He is suspected of murder and attempted murder.
It was just after 8 pm on Saturday evening that several shots were fired in Brynäs in Gävle. Two people were hit by the bullets, according to the police "young men in their late teens". One of them died on the spot and the other was taken to hospital. He is reported to have serious, but not life-threatening, injuries.
The first patrol on the scene found a man who had been shot in the leg, says Temo Allenbäck, local police chief in Gästrikland.
Shortly afterwards, they found another person a bit further away who was declared dead on the spot.
The police believe that the victims were the intended targets.
All those involved are known to us. They are linked to criminal environments here in Gävle.
Find in bush
On Sunday, the police found a pistol-like object in a bush near the crime scene, reports SVT Gävleborg whose reporter was on the scene when the discovery was made. The police do not want to comment on the discovery.
Four areas were cordoned off on Saturday evening around the crime scene, a park near a school.
The police are looking for witnesses to the incident, including owners of Tesla cars in the area whose video cameras may have captured the incident or people or vehicles of interest to the police.
We have reason to believe that there are people who have made observations, says the police's press spokesperson Magnus Jansson Klarin.
"Infected"
Three weeks ago, six people were shot in central Gävle. A 13-year-old boy was arrested in connection with the crime scene. Last week, a young man was shot in nearby Sandviken. Both crimes can be linked to gang crime, according to the police.
Temo Allenbäck does not want to comment on any possible connection to Saturday's shooting, but notes that it is "infected" in Gävle's criminal environments.
We have good knowledge of who these individuals are and a high presence in the city districts where they are, but we cannot always be everywhere. We were prepared but could not prevent this.
About twenty serious violent crimes in gang environments - some of which have been stopped - have affected the police region Mitt, which includes Gävleborg, during a four-week period. The majority of the suspects are under 15 years old, according to the police.
