A second person has been arrested in connection with the truck attack in the Swedish capital of Stockholm earlier this month.
The suspect was arrested on Sunday, but police have not released any details other than stating it was a man.
The Swedish Prosecution Authority statement said on Monday that the prosecutor must decide by Wednesday at the latest whether to request that the man be held on remand.
Four people were killed on April 7 when a hijacked truck ploughed through a busy pedestrian area in central Stockholm.
Rakhmat Akilov, a 39-year-old man from Uzbekistan, is the chief suspect. The Stockholm District Court ruled on April 11 that he be held on remand until May 11.
The Stockholm attack was the fourth time a vehicle has been used to target a crowd of civilians in Europe in the past 12 months, coming after deadly attacks in London, Berlin and Nice.
Police later said the second arrest followed the examination of unspecified material gathered after the attack.