British Columbia ? For the fourth time in less than a year, a human foot in a running shoe has been found along the British Columbia coast.

Police said Friday that they don’t know if there are any links between the cases of the four severed right feet found on island shorelines in the Vancouver region.

Authorities say they haven’t reached any conclusions about the origin of the feet. But local speculation has been rife with some reports claiming they belonged to victims of violent crimes or a plane crash.

Police said a passer-by found the fourth human foot on Kirkland Island, about 15 miles south of Vancouver on Thursday.

“It’s certainly a mystery we intend on solving,” Police Constable Annie Linteau said. “It’s certainly very unusual.”

There is no evidence to suggest the foot – or any or the previous three – was forcibly removed, Linteau said.