A training building -- where Illinois firefighters practiced their skills -- was destroyed by a massive blaze hours after they left.
Firefighters from a number of departments had spent Thursday morning setting fires and extinguishing them in the 6,000-square-foot building, Libertyville Chief Rich Carani told NBC reporters.
The drill was over, and the building had been unoccupied for a time before crews realized it was really on fire.
The structure is located in a forest preserve, forcing firefighters to haul in water by tankers.
The building was slated to be demolished in a controlled burn following another massive drill on Saturday.
