Investigators trying to determine the cause of Colorado's Alexander Mountain Fire ask for tips

UPDATE: On Aug. 9 investigators announced that the fire was human caused. They also made a more specific request for tips.

While crews continue the fight against the largest of Colorado's current wildfires, the Alexander Mountain Fire in Larimer County, federal investigators are also working hard to determine the cause and the origin. Some or all of the 7,648 acre blaze is burning on U.S. Forest Service land.

On Wednesday morning the Forest Service asked for the public's help in their investigation. They said they are looking for information that might help them as well as any photos or videos that might shed some light on what sparked the wildfire.

Emergency crews first responded to the fire late Monday morning. The fire was near the Sylvan Dale Guest Ranch, about 10 miles west of the Loveland city limits. That's near the mouth of the Big Thompson Canyon. By early Monday afternoon there was a big smoke plume that was visible across most of the northern part of Colorado's Front Range.

People can call the Forest Service Law Enforcement Tip Line at (303) 275-5266 if they have information to share. They can submit videos and photos through a special section of the U.S. Forest Service website.