An attorney for an upstate New York man accused of fatally shooting a 20-year-old woman who was with a group of friends who mistakenly turned into his backcountry driveway called it a "terrible accident" involving a defective gun as arguments in his murder trial began Thursday.

Kevin Monahan, 66, is charged with second-degree murder in the death of Kaylin Gillis, who was out with friends who got lost while heading to another person's house on a Saturday night last April.

The group's two cars and a motorcycle mistakenly turned into Monahan’s long, unpaved driveway near the Vermont border. The caravan turned around once they realized their mistake. But Monahan is accused by authorities of coming out on his porch and firing two shots from a shotgun, striking Gillis in the neck with the second shot.

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Attorneys for the prosecution and defense offered starkly different accounts of how those few minutes unfolded in their opening statements.

Kevin Monahan

Defendant Kevin Monahan, center, is flanked by his legal defense during opening statements in his murder trial on Jan. 11, 2024, at the Washington County Courthouse in Fort Edward, N.Y. Monahan is accused of fatally shooting a 20-year-old woman who was with a group of friends who accidentally turned into his driveway. (Will Waldron/The Albany Times Union via AP, Pool)

Assistant District Attorney Christian Morris said Monahan recklessly caused Gillis' death and later provided misleading information about the shooting. He said the group of young friends, mostly teens, had realized their mistake and were turning around. But the second shot hit the Ford Explorer driven by Gillis' boyfriend. She was struck while sitting in the front passenger seat.

"There's a lot of commotion in this car. There's panic now," Morris said, describing the shooting.

Defense Attorney Arthur Frost said Monahan was an old man scared by the group of strangers arriving at his remote home late at night. Monahan gave his wife a revolver before she hid in the closet and then he ventured out onto the porch, according to the attorney.

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Monahan fired a warning shot into the air and watched the vehicles as they left, Frost said.

"And he's walking and he's looking and he stumbles and he bangs the gun. And it goes off," Frost told the jury.

Frost said tests by the police on the gun show it was defective because it fired once when dropped.

"This was a terrible accident. Somebody should have realized that by now," Frost said.

Gillis' friends called for help once they found a cellphone signal several miles away. A 911 call played at the trial revealed the dispatcher guided the panicked friends through CPR while they waited for help to arrive. But emergency workers were unable to save her.

Gillis' father and other supporters showed up at the trial Thursday. Andrew Gillis has described his daughter as someone who loved animals and had dreams of becoming a marine biologist or a veterinarian.

The young woman's death reverberated far beyond the largely rural region about 40 miles (65 kilometers) north of Albany. Gillis died just days after a teen in Kansas City, Missouri, was shot and wounded after going to the wrong house to pick up his younger brothers.

The publicity complicated jury selection this week. Court officials and the trial attorneys spent three days winnowing down a large pool of potential jurors before seating a 12-person panel and four alternates Wednesday afternoon.

Morris has previously described Monahan as "confrontational and hot-tempered." After the shooting, a neighbor said Monahan had grown increasingly bitter over the years at people driving onto his land by mistake.

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Morris on Thursday said Monahan did not call 911 the night of the shooting until police came to his house for a noise complaint and then he suggested it could have been hunters with dogs in the area.

Monahan told a dispatcher he had not heard anything, according to a 911 call played at trial.

"He repeatedly says he wants to go back to bed," Morris said.

Monahan's wife, Jinx Monahan, testified that she didn't see the incident from her hiding spot and that the couple talked about how scared they were afterward.

Her testimony was set to continue Friday.

Monahan, wearing a jacket and tie, listened to the opening statements at the defense table. He was also charged with reckless endangerment and tampering with evidence. He has been in jail since April.

The trial is expected to last several weeks.