7NEWS Investigative reporter John Ferrugias uncovered new information Thursday in the case of Terry Barton, the Forest Service worker who has admitted to igniting the massive Hayman Fire.

Lawyers for Barton have claimed she was unfairly coerced by federal investigators into confessing to a crime and that she was never given the opportunity to have a lawyer present during her conversations with federal agents.

But in a detailed response, the U.S. attorney says Barton was told she did not have to speak to investigators -- and that she was free to leave, but did not. Barton subsequently admitted to setting the fire and signed a waiver of her right to an attorney.

It was after she signed the waiver that she signed a confession and voluntarily re-enacted the crime as agents videotaped her, Ferrugia said.

The U.S. attorney also says Barton voluntarily handed over a matchbook from her truck, telling investigators the missing matches were the ones she used to start the fire.

But the key question remains -- did Barton really burn a letter from her estranged husband in a fire pit and accidentally start a forest fire or did she set the blaze to intentionally burn the forest?

An analysis of the fire pit could not prove conclusively whether there was or wasn't a letter burned to ignite the fire.