Investigators say they're closer to finding out how the Waldo Canyon fire started.

For the first several days after fire was first spotted June 23, it was too dangerous for investigators to go inside the fire lines, resulting in an enormous amount of speculation among residents of the Pikes Peak region, spooked by reports of a serial arsonist in Teller County.

But as firefighters began to gain ground on the fire--which is up to 55 percent containment as of Monday morning--it became safe enough for investigators to get close to the fire's point of origin. Monday will mark investigators' first full day on the ground.

Investigators will need to work quickly to make sure they can discover any and all evidence before it is potentially damaged or washed away in rain waters.

They are optimistic they will soon know exactly how the Waldo Canyon fire was ignited.