The suspect behind the Stockholm truck attack had been facing deportation, Swedish police say.
The 39-year-old man from Uzbekistan is suspected of having driven a truck into a department store in the city on Friday.
Police said on Sunday the man is known to have had extremist sympathies.
His application for asylum was rejected in June last year and he was being sought by immigration officials, police said.
Four people are confirmed to have died in the attack – two Swedish nationals, a Briton and a Belgian, but police have not released their identities.