Two men in their 20s dug the bunker-like tunnel found in north Toronto as a "man cave" to hang out in, police say.

The tunnel, which was discovered in January but first reported by CBC News last week, was dug near York University’s Keele campus and the Rexall Centre, a major tennis venue that's set to host part of this summer's Pan Am Games, as well as the high-profile Rogers Cup tournament.

"It is simply two guys who just wanted to dig a cave," said Toronto police spokesman Victor Kwong.

"That really is what our investigation has led to ... they just wanted to dig a cave to hang out."

CBC News has learned pictures released by the Toronto police investigation helped solve the mystery of the tunnel near York University.

The man who owned some of the equipment which was found at the tunnel saw it on television and called police. He said he had loaned it to an employee — a construction worker who underpins homes.

When police approached the employee and his friend, they admitted they had built the tunnel.

Police deemed the men to have harboured no criminal intent and said they posed no threat to the public. No charges have been filed.

The discovery of the tunnel sparked a wave of speculation about what it might be used for.National security officials were notified in case the tunnel posed a threat to the Games. 

Police said the two men were "very apologetic" for what they'd done. 

The tunnel, which was 10.1 metres long,1.93 metres high and 86.4 centimetres wide, has been filled in. Investigators believe the men began working on the tunnel last September.

Kwong said the men were not connected to York University, Rexall Centre or the Pan Am Games. He also said the men didn't have an engineering background or any formal training in this type of construction. 

Police said "enormous" interest from the media generated a tip that allowed investigators to identify the two men. 

Their investigation into the tunnel is now closed, police said.