Arson claims cast doubt on 'lovelorn' firefighter's forest blaze confession

There is an adage among forest service workers in the United States, meant only half-seriously, that inside every firefighter beats the heart of a secret pyromaniac. That might explain how Terry Lynn Barton, a forestry official of 18 years standing, came to confess that she lit the match that started the worst wildfire in Colorado history.

Prosecutors didn't believe her original story – that she came upon the fire by happenstance – and they are deeply sceptical of her alternative explanation, that she was upset by a letter from her estranged husband and accidentally triggered the fire by burning it at a campsite in the Pike National Forest.

Among the theories being considered is the possibility that she had a "hero complex", that she started the fire to be able to take credit for catching it and putting it out. The theory is Ms Barton did not realise the volatility of the underbrush, and that when she tried to put out the flames they were out of control. John Suthers, the lead federal prosecutor in the case, told the Denver Post yesterday that evidence found near the fire's origin was "not inconsistent" with the hero complex scenario. He said his team was considering other motives.

Today, 12 days after the fire erupted, laying waste to more than 120,000 acres in the mountains south-west of Denver, Ms Barton returns to court for her second appearance since her arrest last weekend. The notion that the culprit could be someone trusted for years to protect the forest has compounded the shock felt in Colorado at the effects of the fire, which has been licking at the outer edges of the Denver suburbs, destroyed dozens of properties and forced thousands of people to evacuate their homes.

Ms Barton, who is 38 and has two teenage girls, was the first official to report the so-called Hayman fire on 8 June, saying she had stumbled upon a burning area roughly 20 feet by 20 feet at a campsite near the town of Lake George.

Within days, forestry investigators concluded there was something wrong with her account. "Given prevailing conditions and the distance Barton reportedly was from the point of origin at the time she smelt smoke, the fire could not have been the size reported by Barton when she allegedly discovered it," an official report stated. Ms Barton admitted she had started the fire. That was when she came up with the story about the letter from her estranged husband. She said she left the campsite thinking she had safely burnt the letter, but returned a few moments later to discover the fire was out of control.

Family members said John Barton rarely wrote letters, and was much more likely to call on her mobile phone. Ms Barton insists she did not set the fire deliberately, a crime for which she could face up to 20 years in prison.

A massive team is tackling the blaze. More than 200 firefighters have been drafted from around the country, with 19 helicopters, 116 fire engines and 11 bulldozers. The fire is about 47 per cent contained, although officials said it could last all summer.