COEUR d'ALENE - Jurors heard directly from Joseph Herrera Thursday in his second-degree murder trial for the shooting death of his 18-year-old girlfriend on Christmas day 2011.

Benewah County Prosecutor Doug Payne played the audio recording of an Idaho State Police detective's interview with Herrera at the St. Maries Police Department just hours after the semi-automatic handgun he was holding fired one shot upstairs in Herrera's parents' St. Maries home. The bullet struck his young, pretty girlfriend of only a few months, Stefanie Comack, in the forehead and then became lodged in a wall.

Herrera, now 29, a St. Maries resident, agreed to talk with Det. Paul Berger without an attorney present, and said the shooting was an accident, the gun going off as he walked through a small bedroom area. He told Berger it all happened very fast, and he had a hard time remembering exactly where Comack was in relation to himself or how she was positioned.

"When I grabbed the slide, the gun went off," Herrera said. It was his father's gun, and he had taken it without permission for self protection because another guy had a "beef" with him.

"I was not very far from her," Herrera said. He said he recalled her "raising up" from a crouched position as the gun went off.

Berger questioned him about how they were getting along that morning, just after Stefanie woke up and was getting ready to go to her family's house for Christmas. He said they were bickering about his not wanting to join her and her family.

"Is there a chance you got upset?" Berger said.

"I would never do anything to hurt her," Herrera responded. He said they'd become practically best friends in the few months they'd been together, spending every night together.

He did admit there was the potential for volatility, as they both had tempers.

Officers found pot and meth paraphernalia in the bedroom, along with a second handgun, this one between the mattress and box spring.

"I smoked some pot right before" she was shot, he said. But, "I didn't shoot her on purpose."

He told Berger the authorities should consider the fact he could have tried to escape if it was deliberate.

Regardless, Berger said, there would still be consequences for shooting Stefanie.

"What kind of consequences are those?" Herrera said.

Berger told him there is evidence the gun was touching her head when it went off, and placed him under arrest for second-degree murder.

"I didn't do anything - please," Herrera pleaded. "It was an accident."

Herrera is going to take the witness stand himself during the trial, so it won't be the last the jury hears from him, his defense attorney said.

Stefanie's family and friends don't believe it was accidental.

Later Thursday, Stefanie's sister, Kaytlin Comack, 23, testified that Stefanie had visited family about a month earlier on Thanksgiving and had finger-shaped bruises on her arm, presumably from Herrera.

Herrera's defense attorney, James Siebe, sought a mistrial at that point because that information had been excluded from the trial.

First District Court Judge Fred Gibler denied the motion for a mistrial.

Siebe said, "I don't know how you un-ring that bell."

Gibler told the jury not to consider that information when making a decision on Herrera's fate.

A friend of Stefanie Comack's, Eunice McEwen, 20, told the jury that Stefanie had told her that Herrera had hurt her.

McEwen, recalling the details of what Stefanie told her in early December 2011, said Herrera allegedly slammed Stefanie's head against a gear shift when the two were in a vehicle together. McEwen said Herrera allegedly choked Stefanie, and held a gun to her head, and allegedly threatened to shoot. Stefanie broke up with Herrera, at least temporarily, after that incident, McEwen said.

McEwen was in the middle of testifying when a power outage early Thursday afternoon in downtown Coeur d'Alene cut the day short. The trial resumes at 9 a.m. Tuesday at the Juvenile Justice Building downtown.

The trial is being held in Coeur d'Alene and not in St. Maries because the two sides were not able to find a jury in Benewah County.