CBC News has obtained these exclusive images of what it looked like inside the confinement room of the abandoned home in Pickering.
The house was destroyed by fire early Friday morning.
The room — which some have described as a dungeon — measured no more than 12 x 8 feet.
According to a source, the room had been freshly painted and fortified when it was discovered by contractors in mid-December.
The images show what looks like a collapsible locker-room bench, with chains hanging from the ceiling.
The doors are crafted from layers of lumber.
The windows are so strong, the source told CBC News, that not even a crowbar could break them.
The room might have been a place to keep a hostage, or could have been a torture chamber, the source speculated.
The water jugs at the end of the bench could indicate that the intention was to keep someone inside for a period of time.
Others have speculated it may have been built as a set for an amateur filmmaker.
Whatever the room was intended for, police say, it was designed to keep someone from getting out. At the time it was discovered they said it was "solely designed to hold someone captive."
But after the fire, it may never be known who built it, or why.