Four people were killed after a small plane crashed into a field near the northwestern Chicago suburb of Crystal Lake, US authorities said Sunday. The single-engine aircraft crashed on Saturday in a farm field in unincorporated McHenry County, officials said. All four aboard were killed. No information was available on the plane\'\'s origin or intended destination, said Federal Aviation Administration officials, who indicated the plane was operating on \"visual flight rules\" and was not in touch with air traffic control. The victims are two men and two women who all appear to be 18 or older, according to McHenry County Deputy Coroner Curt Bradshaw. (QNA) LY