Prosecutor Stefan Lind has previously said that the police investigated the case over the weekend and there was sufficient evidence that would be enough for an arrest.
Now a man in his 20s has been arrested on probable cause, suspected of murder, writes Göteborgs-Posten.
According to the newspaper, parts of the course of events must be captured on surveillance cameras.
It was just before half past six on Thursday evening that the police were alerted to a shooting inside a gym in Tuve on Hisingen in Gothenburg.
A couple of hours later, the news came that a man in his 25s had died after being shot.
Several people were inside the gym and went out in connection with the shooting.
The deceased man was known to the police since before.