(CNN) -- Investigators are pursuing a variety of theories in their quest to unravel the mystery of six human feet that have washed up on the shores of British Columbia in the last 11 months.

An investigator places the shoe and the severed foot inside a container Wednesday.

The sixth foot turned up Wednesday -- a right foot in a man's size 10 black Adidas athletic shoe, police said. As in the previous cases, however, immediate answers as to the foot's origin eluded detectives.

"We are exploring the possibility that it could be people who may have drowned," said Annie Linteau, a spokeswoman for the Royal Canadian Mounted Police. "It could be missing fishermen. It could be the remains of people who may have died in a plane crash."

When asked about the suspicion of foul play, Linteau noted that the first four feet contained no tool marks and were therefore deemed not to have been severed.

It is too early to say how the foot found Wednesday was separated from a body, and Linteau did not address the question of how the fifth foot came to be detached.

"It is certainly a very unusual situation," she said. "We have to explore all avenues and investigate all theories."

The coroner's office plans to examine DNA from the foot found Wednesday to try to identify the person to whom it belonged, she said. The authorities also are combing through missing persons reports and trying to determine when and where the shoe was manufactured and sold.

The sixth foot was found by a woman walking on the beach, said Sgt. Mike Tresoor of the Royal Canadian Mounted Police in the town of Campbell River on Vancouver Island, British Columbia.

"A local citizen walking on a beach in Tyee Spit located what appears to be human remains of a right foot in an approximate size 10 black Adidas running shoe," police said in a written statement.

The foot will be examined by a forensic pathologist, and DNA testing will be requested, said the statement posted on the Royal Canadian Mounted Police Web site.

Sandra Malone, manager of the Thunderbird RV Park and Campground on the spit, said a woman came in about 10:30 a.m. and asked her to call police, saying she had found the shoe with the foot inside it.

While waiting for police, Malone said, she walked to the beach with the woman and saw it for herself.

"You could see the foot that's inside the running shoe," she said. "The leg bones were coming out of the running shoe about 3 to 4 inches. There were no tissues or anything attached."

Don't Miss Fifth severed foot found on Canadian coast

She said seaweed was wrapped around the top of the running shoe, making it hard to tell whether any tissue was inside the shoe. "I got close enough," she said.

But she said the foot appeared to have been deliberately severed, as the bones "had been cut clean across."

The foot was the sixth discovered on shorelines in the area since August, according to local police and media reports. Another foot -- a left foot still in a shoe -- was found Monday on the shore of Westham Island, south of Vancouver. Police said it was taken to a coroner for DNA testing.

"Our first step is to establish identity," said Constable Sharlene Brooks of the Delta Police Department in British Columbia. "It is a little mysterious, but we don't know if it is linked to others."

The Vancouver Sun newspaper said the first four feet found in the area were all right feet, making the foot found Monday the only left foot.

Although the gruesome finds have drawn international attention, police said it may take some time to unravel the mystery.

"We suffer from the 'CSI' effect: People think this can happen very quickly," Brooks said. "It could take weeks or months. And even if we get a DNA sample, we need a sample to match it with."

The mystery has caused a stir and led to many rumors, locals say. One newspaper has began investigating a rash of young men who have gone missing in the area.

Some have wondered whether the feet could belong to five men who were in a plane that crashed three years ago in the waterway where the feet were found.

Some of those men's relatives were at the Campbell River site on Wednesday.

"It's a constant reminder every time, from the time the first foot washed up," said Kirsten Stevens, whose husband, Dave, died in the crash. Although her husband's body was located, Stevens said, the other men's relatives still are awaiting answers. They never recovered their loved ones' remains.

"It reopens the wound every single time," she said.

"If it's not us, it's somebody else's loved one, that they don't know. ... We'd like to know," said Sally Feast, sister of pilot Arnold Feast. "We'd like to put something to rest."

Diane Selkirk, a freelance writer who lives near where one foot was found, said the discoveries have been a hot topic of conversation.

"At first, the talk about it was really humorous, but as more feet turned up, the talk became sinister," she added. "These are pristine islands, not the place where you would expect to find a bunch of severed feet."

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