HINESBURG, Vt. (AP) – A man accused of killing a good Samaritan who tried to stop him from beating his girlfriend told police he “snapped,” according to a police affidavit released Monday.

The girlfriend, meanwhile, said the man who died from the stabbing saved her life.

Roy B. Bash, 20, was held without bail after pleading not guilty to second-degree murder in the death of Scott Gilbeau, 30.

Gilbeau, who was stabbed at least three times in the torso early Saturday, died Sunday at a hospital.

Gilbeau, Bash and two women had been out at a bar in Vergennes before returning to the Hinesburg trailer where Bash and his girlfriend lived. The couples had retired to separate rooms for the night when Gilbeau heard Bash and his girlfriend fighting, according to the affidavit filed by Vermont State Police.

The fight escalated, with Bash punching, kicking and choking his girlfriend and Gilbeau coming to her defense, the affidavit said.

“The next thing I know we are both in the room and I am on top of him, trying to hurt him, trying to punch him, stab him, anything,” Bash told investigators.

He admitted slashing Gilbeau with the knife of his utility tool, the affidavit said.

After the fight, Gilbeau went outside, where he collapsed before being found unconscious by his mother’s boyfriend, who lived next door, police said.

Bash, meanwhile, was found walking down a road nearby, carrying a large knife with what appeared to be blood on it, the affidavit said.

Chittenden County State’s Attorney T.J. Donovan called the case tragic. “He did what, presumably, he thought was the right thing to do at the time, which was to stop an assault occurring,” Donovan said.

Bash, who is originally from North Carolina, was arrested for felony cocaine possession last year and discharging a firearm in city limits in 2005.

He had lived with girlfriend Brandy Larock, 24, for about 10 months, she said Monday, standing outside the trailer.

She said he had abused her numerous times, and that this time, she thought he was going to kill her.

Larock said she pushed Bash off Gilbeau and told Gilbeau to run. She said she saw blood on Gilbeau’s face but thought it was from their fistfight.

Larock and her girlfriend, who had locked themselves in the bathroom during much of the fight, fled to her cousin’s house down the road.

She said she believed Bash was on his way to kill her when he was arrested.

“I should’ve been dead,” she said, crying. “Scott was just trying to protect me … He saved my life.”

AP-ES-10-29-07 1807EDT