FORT EDWARD, N.Y. — A man who fatally shot a 20-year-old woman after the car she was riding in mistakenly drove up his backcountry driveway in upstate New York testified at his trial Friday that he believed he was under siege that night and now feels “like my soul is dead.”

But he maintained the fatal shot went off accidentally.

Kevin Monahan, 66, took the stand in his own defense to end testimony in his second-degree murder trial. He is charged in the death of Kaylin Gillis, who was riding in a caravan of two cars and a motorcycle that pulled into his driveway while looking for another person’s house on a Saturday night last April. Authorities say Monahan fired two shots from his deck, the second of which struck Gillis in the neck.

Monahan told jurors he believed he believed his home in rural Hebron, about 40 miles north of Albany, was “under siege” and facing an “invasion” when the caravan pulled up his long, winding driveway. He came out with a shotgun to try to scare the group away while his wife hid in a closet.

“When you’re by yourself, you have to figure out the worst-case scenario,” Monahan testified, according to the Times Union of Albany. “My only job is to protect my wife.”

Monahan said he first fired a warning shot to let the intruders know that he had a working gun.

“The warning shot, to me, is almost like starting a dialog,” he testified later under cross-examination.

Monahan said he then tripped over nails protruding from his deck while wearing flip flops. He lost his balance and accidentally caused his shotgun to fire at the Ford Explorer carrying Gillis, her boyfriend and two other young friends.

“I didn’t mean to shoot the second shot,” Monahan testified, according to the newspaper. “The gun went off.”

Monahan’s attorney, Arthur Frost, asked him if he pulled the trigger.

“No, I did not,” Monahan said.

Monahan cried on the stand and said the death has left “a hole in me.”

“It’s indescribable,” Monahan said. “I don’t even know how to respond. I just feel like my soul is dead.”

Under cross-examination, Assistant District Attorney Christian Morris asked Monahan if he asked the people in his driveway “Are you guys lost?” or told them to go away.

Monahan said he thought that if he said anything, it would make the situation worse.

Prosecutors allege Monahan showed a depraved indifference to human life by firing at the SUV.

Monahan called 911 later that night when police showed up outside his house. Morris noted that Monahan had said he had been “sound asleep” and never told the emergency operator or police about the incident.

“I didn’t tell the truth,” Monahan said.

Monahan was the only witness called to the stand by his attorneys in his defense before they rested their case Friday.

Closing arguments are expected Monday.

Monahan, who has been in jail since the killing, also is charged with reckless endangerment and tampering with physical evidence.