Colorado investigators seek clues to what sparked wildfires

As firefighters get a better hold on four wildfires burning along the Front Range, attention is shifting to what ignited the blazes.

State of play: The Quarry fire in Jefferson County is now being investigated as arson, but officials declined to elaborate on what evidence is driving that conclusion.

• The flames originated on Deer Creek Canyon Road, where investigators found some "weird items," Denver7 reports .
• "We preliminarily believe this fire is human-caused in some manner," Kevin Bost, the Jefferson County investigations chief, told reporters Friday.

To the north, the Bureau of Alcohol, Tobacco, Firearms and Explosives is providing assistance to the Boulder County Sheriff's Office to determine what sparked the Stone Canyon fire in Lyons. They are asking for the public's help in the investigation.

Authorities have not released details about the origins of the largest wildfire in the state, the deadly Alexander Mountain fire .

Officials determined the Lake Shore fire was human-caused but unintentional.

The latest: Hot, dry weather over the weekend allowed the fires to grow. The Quarry fire is now at 472 acres with 20% containment.

• The Alexander Mountain fire grew to 9,700 acres and destroyed about 50 homes and structures so far. Containment increased to 32%.
• The Stone Canyon fire is nearly contained and all evacuations were lifted Saturday night.