John Etter Clark was born on March 29, 1915, in Stettler, Alberta, Canada. He grew up in a farming family and later inherited a large farm of 1,000 acres that his father had founded. This farm became a significant part of his life as he balanced farming with other pursuits.

Clark worked as a part-time school teacher, sharing his knowledge with students in his community. In 1947, he married Margaret Dinwoodie, and together they had four children. Family life was important to him, and he raised his children while managing his farm.

As he grew older, Clark ventured into politics. He ran for a seat in the Alberta Legislature in 1952, representing the Stettler district. He was part of the Social Credit party and won the election after a close contest. He served as a member of the Legislative Assembly until 1956. He was known as a dedicated public servant, and in 1955, he successfully ran for re-election.

Despite his career achievements, Clark faced personal challenges. He had been hospitalized for a nervous breakdown in 1954 and experienced another health crisis during the spring session of the legislature in 1956. 

On June 3, 1956, Pete Parrott, a neighbor, visited the farm of John Etter Clark in Erskine, Alberta. During his visit, he discovered the bodies of six individuals. Each person had been shot multiple times in the head with .22 caliber bullets. Among the victims were Clark's wife, son, and three daughters. There was also a hired farmhand and a visitor present at the time of the killings. One person was still alive but was critically injured and later died in the hospital.

The Royal Canadian Mounted Police (RCMP) responded quickly to the scene. They sent 14 special field agents to investigate. However, Clark was not found among the dead. He had borrowed a single-shot .22 caliber rifle from his uncle, which was identified as the murder weapon. On the day of the murders, Clark was supposed to travel to Saskatchewan to assist with a political campaign but did not show up.

A search for Clark began. Police found his body approximately 600 yards from the farmhouse. He had died from a self-inflicted gunshot wound to the head. The murder weapon was found lying next to him. Clark was dressed in night attire, indicating he may have been preparing for bed when the events transpired.

The search involved 32 RCMP officers on horseback and an aerial search by a Royal Canadian Air Force Otter aircraft. Clark's body was spotted from the air a few hours into the search. Earlier in 1954 and again in 1956, Clark had been hospitalized after suffering nervous breakdowns. This incident resulted in one of the deadliest mass murders in Alberta's history.