Footprints: How did human feet get washed up on the west coast of Canada and the US?

In August 2007, on an island off Canada’s west coast, the remains of a human foot were found washed up on a beach.

Six days later, on another beach 50 miles away, a second foot was found. But, strangely, it does not match the first - they are from different people.

The BBC’s Celia Hatton travels to Vancouver to hear how more than 20 feet have been found in the area since then, and to speak to the investigators and scientists who have worked to unravel the mystery of why they started appearing.