At approximately 10:45 AM on October 10, 1949, a Canadian Pacific Air Lines Douglas DC-3 flying out of Montreal, and bound for the Quebec town of Baie-Comeau, exploded in mid-air over the town of Sault-aux-Cochons, killing all 4 crew and 19 passengers. An investigation ruled out mechanical failure, and pointed towards an explosion originating from the forward baggage compartment. The hunt was on for the culprits in what was, at the time, the largest mass murder in North America.
The trail eventually led to Marguerite Pitre and Albert Guay, the latter a Montreal jeweler and watchmaker whose wife had been among the victims. While Guay had taken out a $10,000 insurance policy on his wife prior to her departure, this was considered common practice at the time, and in itself was not enough to arouse suspicion. However, within a few weeks of the bombing, either1 Pitre or Guay confessed, and the whole plot was revealed.
In debt, and in love with a 17 year-old girl named Marie-Ange Robitaille, Guay planned the bombing as a way to solve both of his problems in one step. He enlisted the help of an employee, Généreux Ruest, and together they made a bomb based around blasting caps and dynamite acquired by Ruest's sister, Marguerite. Guay then purchased a ticket for his wife, Rita Morel, and convinced her to travel to Baie-Comeau under the pretense of picking up some jewels for his business. The bomb, hidden in a parcel, was delivered to the airport by Pitre, who had the 'religious statue' shipped by air freight via the same DC-3 that Guay's wife would be traveling on.
Following the investigation and trial, Guay, Reust, and Pitre were found guilty, and all three were sentenced to death by hanging. Marguerite Pitre's 1953 execution would mark the last legal execution of a woman within the Dominion of Canada prior to the abolishment of the death penalty in 1976.
In a final footnote to the entire affair, a friend of Guay, Roger Lemelin, turned the case into a novel titled Le crime d'Ovide Plouffe, which was eventually adapted into a screenplay.
1 My sources conflict as to who exactly confessed, with some claiming it was Guay, and others claiming Pitre.