Efforts to resolve British Columbia's missing foot mystery are focused on the relatives of four people who died in a plane crash off B.C.'s south coast three years ago.

The B.C. Coroner's Service has asked family members of the plane crash victims to provide further DNA samples to see if there's a match between their samples and DNA taken from three of the five feet which have washed up on southwestern B.C. shorelines in the last year.

Efforts to resolve the mystery continue after a fifth foot was discovered Monday at the mouth of the Fraser River in the Vancouver suburb of Ladner.

All of the feet have been found in the waters of the Georgia Strait area between Vancouver Island and the B.C. mainland.

The first two feet washed up in August 2007, one on Gabriola Island, the other on Jedidiah Island. Then in February another foot in a running shoe appeared on Valdes Island.

Last month a fourth foot was found on Kirkland Island in the Vancouver suburb of Richmond.

And on Monday, foot number five, showed up in Ladner. It was the only left foot so far.

Dr. Gail Anderson, of the Simon Fraser University Centre for Forensic Research,  believes the five feet are connected.

"Perhaps a plane going down, a boat going down, where a number of deaths have occurred,'' she said.

"Perhaps something has happened, the tide has shifted, another boat has hit it, something has happened to move it."

Kevin Decock's two brothers were onboard the plane which went down near Quadra Island in the Georgia Strait three years ago. He has spent countless hours searching for their bodies, and the bodies of two others onboard.

"I dragged a hook along the bottom looking for the motor and I believe I could have stirred something up,'' he said. It was two weeks after that that the first foot showed up.

B.C.'s chief coroner Terry Smith said foul play is not suspected in this case. "There is no other process on going other than disarticulation of the feet,'' he said.

A resolution to the mystery can't come soon enough for the families of the missing plane crash victims, who are waiting for news of their loved ones.

With a report by CTV British Columbia's Carrie Stefanson.