VANCOUVER, British Columbia — A fifth human foot in a year has washed ashore off the coast of British Columbia. Police said two people out for a walk spotted the left foot floating in water off Westham Island on Monday morning.

Delta Police Const. Sharlene Brooks said officials are working with the B.C. Coroner's office to see if foot is linked to any other partial remains recovered in the province. Westham Island is at the mouth of the Fraser River, about 15 miles south of Vancouver.

"A passerby noticed a shoe floating in the water, pulled it in and notified police," Brooks said. "We're treating it as a criminal investigation."

While the similarities to the other feet are strong, she said there's no indication this foot is related to the other cases.

The last foot was found May 22 on Kirkland Island in the Fraser River, about one mile away from Monday's discovery.

The first in the series was found nearly a year ago on Jedidiah Island in the Strait of Georgia. Within days, another right foot was found inside a man's Reebok sneaker on nearby Gabriola Island. The third was found in the same area, on the east side of Valdez Island in early February.

The origin on any of the remains is still unknown.

Brooks said in order to identify the foot, other remains or identifying material such as a DNA would be needed. "It's going to be pretty difficult."

The Royal Canadian Mounted Police has said there's no evidence the feet were removed from the victims' legs by force. Curtis Ebbesmeyer, an oceanographer based in Seattle, Wash., said when a human body is submerged in the ocean, the main parts are usually what come off the body.

He said his theory is that the feet came apart as a result of an accident.