Diane Déry was 13 when she left with her neighbor and friend Mario Corbeil on the evening of May 20, 1975, in Longueuil, Quebec. They rode a red Kawasaki motorcycle into a familiar trail and wooded field off boulevard Rolland-Therrien and vanished. The following morning, both were found shot repeatedly in a vacant wooded area; Diane suffered two gunshot wounds, one entering the back-right area of her head or neck and another through her left armpit that passed through both lungs and damaged the pulmonary artery. Powder residue indicated at least one close-range shot.

Ballistics pointed investigators toward a .22 Long Rifle semiautomatic, specifically a Cooey Sure-Shot type rifle. In 1977 police arrested or detained nine people and searched ten locations, seizing several .22 rifles including a Cooey Sure-Shot Model 64, but records do not show final ballistic results or any murder charges. The killings remain officially unsolved and under review.

Did anyone in the Longueuil area recall seeing Diane, Mario, or that red Kawasaki on the night of May 20, 1975?