People who know the woman accused of setting Colorado's largest wildfire said Sunday the 18-year U.S. Forest Service veteran had dedicated her life to working in the wilderness.

Terry Barton, 38, admitted she burned a letter from her estranged husband at a campfire site in the Pike National Forest while patrolling to enforce a fire ban, assistant U.S. Attorney Bill Leone said Sunday.

The fire, which started June 8, then got out of control. Barton initially told investigators that she discovered an illegal campfire and tried to put it out.

Joan Spigner, who runs a convenience store in Lake George, said Barton has been a customer for years.

"She was really liked by everybody, a swell person and hard worker for the Forest Service. I don't know what made her set that letter on fire. She should have burned it in her wood stove," Spigner said.

"The Forest Service was her life. She worked really hard. She came in really tired," she said.

Barton was arrested on federal charges of setting fire to timber in the national forest, damaging federal property and making false statements to investigators.

Barton worked for the Forest Service for about 18 years, first as a seasonal employee part-time, and less than a year as a part-time employee year-round.

More than 200 people packed into a school gym in Lake George Sunday evening for an update on the fire that had burned more than 100,000 acres and forced 5,400 people from their homes.

Park County Sheriff's Sgt. Dan Anthony announced there had been arrest in fire and the crowd cheered. But when Joe Meade, acting superintendent of the Pike and San Isabel national forests announced who was arrested, the crowd suddenly grew quiet.

"She didn't go out there and make a fire to burn down our forest," said Jody Penny, 45, who was evacuated from her Florissant Heights home on Tuesday but didn't know Barton. "She went up there to burn up a letter and be real down."