Robert Raymond Cook (July 15, 1937 – November 15, 1960) was a Canadian man accused of one of Alberta’s most notorious crimes — the mass murder of his entire family in Stettler during June 1959. Victims included his father, stepmother, and five young half‑siblings (ages 3 to 9), all found brutally killed: the adults shot with a shotgun and the children beaten to death and concealed in a grease pit beneath the garage. Cook was arrested days earlier for attempting to trade in his father’s car using falsified documents—inside which police discovered family mementos and children’s pyjamas, raising deep suspicion. Although charged with all seven murders, he was only tried for his father's death to expedite proceedings; convicted in two trials and denied clemency, he was executed by hanging on November 15, 1960, becoming the last person to be executed in Alberta. To this day, his case remains controversial, as many locals and even his defense attorney expressed lingering doubts about his guilt.