CHICAGO -- A mysterious "murder" film turned out to be no mystery at all after police discovered the evidence was really made for a rock music video.

The film, found in a movie camera lying in a Michigan cornfield last year, shows Trent Reznor, lead singer for the Cleveland rock group Nine Inch Nails, lying face up in an alley on Chicago's North Side.

Chicago police Detective Hal Ardell said Tuesday that the rock group made the film last September, using 8mm movie cameras held aloft by helium balloons for some of the scenes. But a tether broke and the balloons carried one of the cameras to a cornfield 125 miles away, near Burr Oak, Mich.

The farmer who found the camera turned it over to Michigan state police, who developed the film and sent a copy to the Chicago police.

Pathologists at the Cook County medical examiner's office said it appeared Reznor was dead. But Ardell said it was starch powder placed on Reznor's face that gave him the deathly look.

Inquiries at college film departments turned up a former Art Institute of Chicago student who said his employer, H-GUN Video Productions, had been hired by a New York firm to produce a music video for Nine Inch Nails. The man explained how the camera broke loose.

"The bottom line is we don't have a body and we don't have mystery or homicide," said John Townsend, chief of detectives of the Chicago Police Department.