WEST DES MOINES, Iowa -- West Des Moines police said that if two photos of boys tied up and gagged are not of Johnny Gosch, then someone is playing a "horrible prank'' on his mother. Gosch was 12 when he disappeared in 1982 from his West Des Moines neighborhood while delivering the Sunday newspaper.

Police are investigating a lead out of Florida that the pictures recently delivered to his mother's front door date back to the 1970s. A retired investigator from the Hillsborough County Sheriff's Office in Tampa said the photos of boys tied up and gagged are not Gosch.

The sheriff's office is now going through every roll of microfilm in its archives to find the police report, which has the photos attached. West Des Moines police Lieutenant Jeff Miller said the investigation is continuing to look into who dropped the photos off at Noreen Gosch's house. Calls for comment have not been returned.

Nelson Zalva, a retired police detective in Tampa, Fla., who now works for the Florida state attorney, said that he believes these are pictures from a case he worked on in the late 1970s -- that's several years before Gosch disappeared. He said at the time, police tracked down and identified all three boys and the man who took the pictures.

Zalva said the boys posed voluntarily and police did not file charges. He does not believe these three boys have anything to do with the case.