Frozen Evidence

In 1992, two masked gunmen enter the Canadian home of Ward and Diana Maracle to rob them, but Ward was shot in the head. If a perpetrator leaves a shoe print in the mud, investigators use established techniques to make a mold of the shoe impression for later identification. In this case, the impression is left in the snow. Here's the story of one investigator, whose quick thinking and knowledge of science enabled him to capture a shoe impression made in snow, before the evidence melted away.