Is it the work of an organized crime ring? Are they remnants from bodies that have floated across the Pacific Ocean following a tsunami more than a decade ago? Perhaps a serial killer with a particularly twisted signature is on the loose in the Pacific Northwest?

Speculation surged once again Tuesday following Monday’s announcement by Canadian authorities that a human foot had washed ashore in Vancouver -- the 15th such occurrence in British Columbia in just over a decade. The grisly phenomenon has captivated the minds of the public and media for years, with theories of the feets' origins ranging from natural disasters to something more sinister.

“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,” a man who made one of the morbid discoveries told The Guardian in 2008. “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.”

One theory, the Toronto Star has previously reported on, links the feet washing ashore to missing bodies from a plane crash that happened near Quadra Island in the Vancouver area in 2005. Another, The Guardian says, ties them to human remains that have – with the help of ocean currents – drifted across the Pacific following the Indian Ocean tsunami of 2004.

FOOT DISCOVERED ON CANADIAN ISLAND BELONGS TO WASHINGTON STATE MAN

But despite all the speculation, officials tasked with investigating the feet say the most likely explanation is that they're coming from people who died by accident or committed suicide – and the feet are floating ashore in the Pacific Northwest simply due to Mother Nature.

“Things that float at the ocean surface move with the currents, but also are pushed a bit by the wind, and this can be significant in getting them to shore,” Parker MacCready, a University of Washington oceanography professor, told Vox while talking about the Salish Sea, a body of water that neighbors the Strait of Georgia, where many of the feet have been found.

“The prevailing winds here are west to east, and so floating stuff in this part of the Pacific gets blown to the coast effectively,” he added.

The foot that made the headlines Monday was found in September 2018 along the Vancouver shoreline in blue socks and a grey Nike sneaker.

British Columbia’s coroner's service has determined that the latest foot belonged to a man yet have been unable to match its DNA with any databases. An identification specialist said the foot’s former owner was most likely under the age of 50.

The fact that the foot was found encased in a sports sneaker is key to it being discovered. Had it not been inside one, the foot may have sunken to the sea or ocean floor, or have been consumed by wildlife, experts say.

“Feet easily disarticulate and when they are attached to a flotation device such as a running shoe, they are easily washed ashore,” Gail Anderson, co-director of the Center for Forensic Research at Simon Fraser University in British Columbia, told Vox. “Notice there are no feet washing ashore in stiletto heels or flip-flops. Also, today’s running shoes are much more buoyant than in the past.”

Forensic investigators who have examined the feet over the years have ruled out foul play, The Guardian reported last year, noting that “none of the feet showed signs of trauma.”

Some of the feet that have washed up have been faked, a former official with the British Columbia Coroner’s Service said.

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

But for those real ones – and likely the case with the foot that made the news yesterday -- it's likely a mix of natural human activity, improved footwear and Mother Nature that is driving the phenomenon.

Fox News' Bradford Betz contributed to this report.