Transcript for The Hunter Whose Campfire Started the Yosemite Rim Fire
Thank you so much, jon. Now we turn back here at home to a mystery solved. It seems almost impossible but we have learned that caused the giant wildfire that almost destroyed yosemite. Tonight the forest service believes one man, one hunter with one camp fire lit the flame that almost destroyed the ANCIENT SEQUOIAs. Here's abc's clayton sandell. Reporter: Firefighters don't know when they'll stop the massive rim fire, but tonight they know how it started. Officials today blamed a hunter for burning an illegal campfire that got out of control. In just 20 days it's all ready chewed through more than 370 square miles of forest and an area bigger than dallas, text, and over 100 structures. Cost so far? 77 million. That unidentified hunter has not been arrested, but may be on the hook to pay back at least some of the cost. The forest service says nearly nine in ten wildfires are caused by people. One of the reasons they're rollin gout smokey the bear 2.0. Reporter: In new public service announcements, conscientious campers get hugs. Only you can prevent wildfires. One person may have destroyed a national treasure. Yosemite national park. Clayton sandell, abc news, colorado springs.
This transcript has been automatically generated and may not be 100% accurate.