Gordon Edwin Sanderson was a 26-year-old Indigenous man from Manitoba who had been living in Edmonton and is now identified as the long-unidentified victim known as Septic Tank Sam. His badly decomposed remains were recovered from a six-foot-deep septic tank on an abandoned rural property in the Lindbrook area, west of Tofield, on April 13, 1977. The body had been wrapped in a yellow bedsheet, bound with nylon rope, and quicklime had been placed with the remains.

Examination showed an exceptionally violent killing: Sanderson had been beaten, restrained, deliberately burned with cigarettes and a small butane torch, mutilated with a sharp instrument and fatally shot in the head and chest with a small-caliber firearm reported in some accounts as a .32-caliber. Investigators believe the tank was a disposal site and that the nature of the violence suggests someone who knew him. Identification came decades later through forensic genetic genealogy; his identity was announced publicly in June 2021.

No arrest, charge or conviction has been reported and the homicide remains unsolved. Anyone who knew Sanderson, his movements in Edmonton, or his associates in the months before his disappearance is asked to come forward with information.