OAKDALE, Ill. (AP) – A pilot killed when a helicopter crashed in rural southern Illinois was crop-dusting at the time, authorities said.

Donald L. Pruett, 41, of Mount Vernon, was pronounced dead at the scene July 31 by Washington County Coroner Mark Styninger. Pruett was the sole occupant of the helicopter.

The wreckage was found in a cornfield under overhead power lines, the coroner said. It was unclear if the helicopter struck the power lines.

The cause of death appeared to be blunt force trauma pending an autopsy, Styninger said.

The Federal Aviation Administration (FAA) said the helicopter was a Bell UH-1H “Huey.” The FAA and the National Transportation Safety Board are investigating the crash.

Oakdale is s southeast of St. Louis.