British Columbia, Canada is known for many things: beautiful landscapes, great skiing, the 2010 Winter Olympics – and the human feet that have been washing up on its shores for the last nine years.

Since 2007, 14 human feet clad in running shoes have been found on the shores of British Columbia, from Jedediah Island to Botanical Beach. So far, the provincial coroner’s office has identified eight of the 12. Of those eight, there were two pairs. The remaining lone feet, the coroner determined, belonged to men.

Between 2012 and 2016, there was a four-year pause between sightings. Then on 7 February a new one washed ashore, discovered by a hiker along Vancouver Island’s Botanical Beach. Five days later, another one appeared. The coroner’s office confirmed they were a pair.

A trainer containing a foot that washed ashore in British Columbia. Photograph: BC Coroners Service

After so many years, the arrival of human feet no longer provokes concern in the province. But when they first started to appear in 2007, speculation about where they came from ran rampant and pranksters even planted fake feet on the shores, just to add fuel to the fire.

“We’ve had people put dog foot skeletons in runners and leave them on the beach,” Barb McLintock, who works at the coroner’s office, told the Guardian in 2016. “And somebody even used old chicken bones.”

Since the first foot was discovered, theories about the feet have been numerous and creative. In 2008, a Toronto Star article said that “speculation ranges from natural disasters, such as the tsunami of 2004, to the work of drug dealers, serial killers and human traffickers”.

In 2008, the man who found the fifth foot told the Guardian he suspected foul play: “There’s someone doing this all right. Think about it, if they tied a chain around someone’s ankle and threw them overboard, the foot would just pop off. That could explain it. Maybe they got a lot of bodies stored up in a container and they got washed out. We don’t know. There’s a lot of stuff goes on over there,” he said.

But McLintock said this was not the work of a serial killer or the result of alien abductions. The coroner’s office has ruled that all of the identified individuals committed suicide or died accidentally, most likely due to storms near the coast.

After several years and a dozen cases, McLintock said their work suggests the feet are separating from the bodies during decomposition. This occurs more quickly underwater than it would on land.

“The forensic anthropologists can be really sure of that because they can tell looking at the ends of the bones whether they disarticulated naturally or whether there’s any sign that any mechanical force has been applied to them, whether there’s any trauma, whether there’s any tool marks on them,” she said. “And none of them have had anything like that. All the evidence is pointed to just this natural articulation process.”

But some people still have questions – for example, why did the feet only start turning up after 2007? The answer may be advancing shoe technology. More and more sports shoes are using air pockets or light foam in their designs, which “eventually allows them to be light enough to float and to wash up on shore”.

The coast of British Columbia sees many of these cases because of tide and current patterns, according to McLintock. And while the odd foot pops up elsewhere in the world – for example, several have come ashore in Washington state – British Columbia remains in the spotlight. But McLintock has no doubt that this occurs worldwide, and not just on her coast.

“Presumably there probably are a bunch of running shoes bouncing around out there,” she said. “But no one’s ever going to find them.”