Volunteers picking up trash on the Seattle waterfront Tuesday found a sneaker with human remains inside, according to U.S. media.

The foot was found on the shore near Centennial Park and sent for medical examination, the Seattle Times reported.

At least a dozen human feet have been discovered off the B.C. and Washington State coasts since 2007, though police never found any signs of foul play. At least four feet were linked to people who died of natural causes.

The BC Coroners Service said the feet appear to have separated naturally from bodies in the water.

There have also been a number of hoaxes, including a series of child-sized shoes that were left stuffed with non-human remains on a Victoria beach.