Finnish police authorities said they arrested an Iraqi man on suspicion of taking part in a 2014 mass killing of Iraqi soldiers by Islamic State militants.
As many as 1,700 mostly Shi'ite Muslim soldiers were killed after they attempted to flee the former U.S. military base, Camp Speicher, when it was overrun by IS in 2014.
The 24-year-old Iraqi, who was not identified, was likely a member of IS at the time, Finnish police said on August 24.
The man entered Finland in August 2015. Authorities did not say whether the man sought asylum. Most of the 32,500 people who sought asylum in Finland last year came from Iraq.
Finnish police are also investigating two other Iraqi men for possibly participating in the shooting of 11 unarmed prisoners at Camp Speicher, in an incident filmed by IS.
Iraq hanged 36 militants on August 21 over the mass killing at the base near Tikrit in northern Iraq.