Victor Ernest Hoffman was born in 1946 in Saskatchewan, Canada. Little is known about his early childhood, but by his teenage years, signs of serious mental health struggles began to show. Hoffman was diagnosed with paranoid schizophrenia and had spent time in a mental institution prior to the murders. He was released from the Saskatchewan Hospital in North Battleford just three weeks before he committed the crime, reportedly against his family's wishes.

In the early morning hours of August 15, 1967, Victor Hoffman entered the Peterson family home in Shell Lake, Saskatchewan, carrying a .22-caliber rifle. Without warning or reason, he proceeded to shoot nine members of the family in the head as they slept. His victims included James Peterson (the father), his wife Evelyn, and seven of their children, ages ranging from 2 to 17. The only survivors were the oldest son, who was not home at the time, and the youngest child, a 4-year-old girl named Phyllis, who was found unharmed under the bed.

The murders shocked Canada. The randomness and brutality of the act left the community and the entire country shaken. Hoffman was arrested the next day, August 16, 1967. He confessed quickly, telling authorities, "I just had to kill them."

He was found not guilty by reason of insanity and was committed to a mental health facility for life. Hoffman remained institutionalized until his death from cancer on May 21, 2004.