Mario Cardinal was 26 when he disappeared from Trois-Rivières, Québec. He was last seen on August 2, 1972; his family reported him missing when he did not return. The Sécurité Publique de Trois-Rivières opened an investigation and has kept his file open.

At the time he vanished he was described as a white male, brown hair, brown eyes, 5 feet 9 inches and about 157 pounds. He was reportedly wearing blue denim pants, a white cotton vest, and brown leather boots. A tiger tattoo on his right upper arm was noted as a distinctive mark.

Much about his movements that day and any possible reasons for his disappearance remain unknown to the public.