Brooke spoke with Denver Firefighters Museum director Win Farrell about a spooky photo that was taken in 2010, and how it pertains to the investigation. The photo takes the shape of what many people describe as a ghost.

"[The photo] was captured on a true infrared camera that sees all the way into the light on an infrared spectrum, and I was actually facing the camera towards [a] bookcase when I took a series of pictures and in one of the photos, that apparition showed up," Farrell said.

Ferrell also speculated about the history of the museum and how it ties into the alleged ghost photo.

"That intrigue of the history of this old museum really gets us every time. And the historic factors with the fire department," Ferrell said.

The building has come a long way since being a horse's stable back in 1909.

Back when it was a fire department, the coal shoot and hose extended into the basement where the photo was taken. This evokes suspicion among people at the museum, thinking the so called ghost from the photo is of an old firefighter.

Past 9NEWS investigations include the Melting Pot in Littleton and a bed and breakfast in Highlands.

For more information, you can go to http://www.denverfirefightersmuseum.org/.

Nate Chisholm contributed to this report.

(KUSA-TV © 2012 Multimedia Holdings Corporation)