The driver of a pickup who fatally injured three Girl Scouts and an adult has been arrested in Chippewa County. The scouts were part of a group picking up trash in a ditch in Lake Hallie Saturday. Twenty-one-year-old Colton Treu was driving the truck which went out of control and hit the victims. Initially, he failed to stop, but he later turned himself in. The names of the victims have not been released. A fourth Girl Scout is hospitalized in critical condition.