Swedish police have charged one person for committing terrorism by murder. The prosecutor took the decision at 2am on Satuday, after the person was arrested on Friday evening in the Stockholm suburb of Märsta.
Police spokesperson Lars Byström says to Swedish Radio "As I understand the person is charged with being the perpetrator, so it is probably the driver." But he also says the details are up to the prosecutor.
Before 12 on Tuesday the prosecutor must get a court order to be able to hold the suspect.
Police say to news agency TT they have no other comments on other possible arrests.
Swedish Radio News has learned that the suspect is from Uzbekistan. This information comes from German state agencies, who the Swedish authorities are cooperating with and sharing information. There is no information about a connection to Germany.
Border controls are in place for people travelling in and out of Sweden, but the terror alert level is unchanged, at higher than normal.
Most train and bus traffic is going as normal. But some regional trains in Mälardalen, southern Sweden and towards the central city of Gävle are cencelled, says the Traffic Authority to Swedish TV news.
After the suspected terror attack in Stockholm nine people are still being treated in hospital, including one child. Six people left the hospital during the night, including one child.
The Swedish security police Säpo, who handle intelligence and counter-terrorism work, are treating the case as a terror crime.