When a police patrol saw the boy get out of the driver's seat in the center of Torneå at two o'clock, they drove forward to check his ID documents - but then he tear-started and drove away.
Two patrols joined the hunt, which went on in pouring rain and poor visibility. Eventually, the boy lost control of the car and drove into a tree grove.
Three passengers were in the car, which had to be cut up to remove two of them - a 16-year-old girl and a 16-year-old boy. The third, a 14-year-old boy, was found injured next to the car.
The 12-year-old boy was found near the scene of the accident, admitting he was the driver. All children were taken to hospital, but their injury status is unknown.