Opening statements began Thursday in Washington County where Kevin Monahan, the man accused of fatally shooting 20-year-old Kaylin Gillis in his driveway last spring, is standing trial. During the afternoon, the first witnesses took the stand.

Prosecutors said the 66-year-old man acted recklessly in responding to a group of teens lost and turning around in his driveway, while the defense chalked it up to a terrible accident.

In his opening statement, prosecutor Christian Morris laid out for the jury what he calls the facts: that on April 15, 2023, three vehicles — a motorcycle, Jeep and Ford Explorer — traveled up Monahan’s long driveway after mistaking it for a party Gillis and a group of her friends were going to in Hebron.

Morris says the group of vehicles stopped about 30 yards shy of Monahan’s house while the teen driving the motorcycle continued up the driveway towards the house to make sure it was or wasn’t the right spot. It only took him about 20-30 seconds, Morris said, to realize the house was dark, and he returned to his friends further down the driveway.

After a brief conversation — less than three minutes, according to Morris — the group began leaving. In the midst of a three-point turn, Morris said, the friends in the two SUVs noticed the lights come on and saw a man on the porch with a gun. Two shots rang out within five seconds of each other, the second fatally hitting Gillis in the neck. She was in the passenger seat of the Ford, the last vehicle Morris said was making its way down the driveway.

Monahan’s lead defense attorney, Arthur Frost, called the events “a terrible accident.” He said Monahan and his wife are early risers who go to bed early and were caught off guard by the vehicles in their driveway.

Frost said Monahan recalled the motorcycle “roaring” up his driveway. After Monahan fired a warning shot into the air, Frost said, the vehicles appeared to be leaving. But he said that as Monahan stepped forward on his deck, he stumbled, and what ended up be the second, fatal shot went off by error.

Frost said testing will show that the 12-gauge shotgun in question is old, defective and can fire without the trigger being pulled.

“Kevin has his gun. He’s walking and he’s looking, he’s walking and he’s looking and he stumbles, bangs the gun and it goes off,” Frost said, adding that testing of the gun will prove it to be old and defective.

“This was a terrible accident, and somebody should’ve realized that by now,” he said.

About 20-30 witnesses are expected to testify over the course of the trial, which is expected to conclude before the end of the month. Frost did not say if Monahan would take the stand and spent a considerable amount of time in jury selection asking potential jurors if that would affect their ability to deliver a fair verdict.

Testimony continues Friday morning.