Story highlights

An elaborate tunnel was discovered near Pan Am Games venue in Toronto

Nothing so far suggests criminal activity or terrorist intent, police say

Police Deputy Chief Mark Saunders: "There is no criminal offense for digging a hole"

CNN  — 

A big hole in the ground discovered near a venue for the 2015 Pan American Games in Toronto has stumped authorities looking into it.

The mysterious tunnel measured more than 6 feet in height, nearly 3 feet in width and about 33 feet in length, Toronto Police Deputy Chief Mark Saunders told reporters Tuesday.

Plywood walls were reinforced with wooden supports. The tunnel was 10 feet underground, with a ladder leading down to the chamber.

A rosary with a Remembrance Day poppy hung from a nail on the wall. Remembrance Day honors Canadian service members who died in combat.

“What does that tell you?” a reporter asked the deputy chief.

“That tells me that this was nailed inside the tunnel on the wall,” Saunders deadpanned.

A rosary with a Remembrance Day poppy hung from a nail on the wall of mysterious Toronto tunnel.

Nothing so far suggests criminal activity or terrorist intent, Saunders said.

“I wasn’t overly concerned that ‘Oh my goodness this is going to be something horrific,’” said the chief, a 31-year veteran of the force.

The discovery of the tunnel – which was made by a conservation officer last month, but disclosed Tuesday – comes amid heightened concerns about terrorism in Canada and beyond.

In October, a soldier was shot and killed as he stood guard at Canada’s National War Memorial in Ottawa. Officials said the gunman had connections to jihadists who shared a radical Islamist ideology.

Two days before the Ottawa attack, another Canadian soldier in Quebec was run over and killed by a man whom the Royal Canadian Mounted Police described as “radicalized.”

Mystery tunnel discovered in Toronto.

“There is nothing right now that suggest that this is criminal,” he said. “We’re trying to find and establish right now who built it, why they built it and what were their intentions.”

“There is no criminal offense for digging a hole.”

Authorities are seeking information from the public about any suspicious activity in the area.

The tunnel was equipped with electricity supplied by a generator, a sump pump to remove water and a pulley system to remove dirt, Saunders said. It likely took more than one person to dig it out by hand. Ice that formed at the end of a hose attached to the sump pump indicates that the tunnel may have been used this winter.

“This was built with a considerable amount of sophistication,” Saunders said. “The individuals responsible for building it clearly had some expertise in structural integrity.”

Police also found a gas can, food and beverage containers, work gloves, a wheelbarrow and moisture-resistant light bulbs in the tunnel. Dirt covered a wooden lid that concealed the tunnel’s surface entrance.

“We don’t know whether someone is building one somewhere else,” Saunders said. “I’m open to anything right now.”

The Pan American Games, which take place from July 10 to July 26, involve nearly 7,000 athletes from Latin America, South America, the Caribbean and North America. It is the third largest international sports competition after the Olympic Summer Games and the Asian Games.

CNN’s Chuck Johnston contributed to this story.