HEBRON, N.Y. — The man who lived on the ridge above this little upstate town had long had a reputation among some residents as a sour character who barked at neighbors’ dogs, scolded a local church and was so averse to unannounced visitors that he had at one time used a chain to cordon off his quarter-mile-long drive.
On Saturday night, just before 10 p.m., Kaylin Gillis and a group of her friends were traveling in a caravan of two cars and a motorcycle that mistakenly drove up that same driveway. They were looking for a friend’s house — and were met with deadly gunfire, killing Ms. Gillis, 20.
It was warm, but overcast and dark, and the three vehicles, according to the county sheriff, turned off a highway, up the largely dirt road on which the man, Kevin Monahan, 65, lived, past several other homes.
They soon took a right turn into his drive, which is flanked by a tree with two worn “private property” signs, warning off trespassers, and a small “private drive” sign.
On Tuesday, a nearby resident, who declined to give his name because of the sensitivity surrounding the killing and the investigation, said he watched vehicles ascend the steep drive, their lights on, before seeing the motorcycle turn and start to descend.
Then, he heard a shot, followed by several seconds of silence. Then, a second shot rang out, though he and his wife initially believed it might have been fireworks.
“Our neighbor down the hill called and said, ‘Did you hear gunfire up there?’” the resident said. “And we said, ‘Oh, we heard something.’”
He said he immediately called 911. But in an indication of how difficult the area is to navigate, those police officers initially also went up the wrong driveway, so he called 911 again. “It’s hard to get your bearings unless you’re from here,” he said.
Ms. Gillis’s death shocked residents in the area and leaving the nation to wonder at yet another seemingly senseless gun death.
Mr. Monahan was charged with second-degree murder in an attack that the Washington County sheriff, Jeffrey J. Murphy, described as unprovoked and unexplained.
“There was no threat,” he said on Tuesday. “They were leaving.”
The killing came just days after another shooting in Kansas City involving a Black 16-year-old, Ralph Yarl, who was shot by an 84-year-old white man after mistakenly going to the wrong house while trying to pick up his brothers at a friend’s home on Thursday evening. He survived but was badly injured.
Unlike that case, what happened in Hebron did not have racial overtones: Ms. Gillis was white, and so is Mr. Monahan. But the aggression of the encounter and the idea that a simple wrong turn led to death nonetheless left many here and elsewhere shaken and wondering what prompted Mr. Monahan’s actions.
“I can’t imagine that this is something that someone who is my neighbor is capable of,” said Adam Matthews, who lives next to Mr. Monahan. “I don’t know what brings someone to that level.”
According to Sheriff Murphy, Ms. Gillis was one of four people in the last vehicle to turn around and was sitting in the front passenger seat when Mr. Monahan shot through the rear of the driver’s side.
“They all were still in proximity to the house and they all heard two gunshots,” he said. “They realized immediately that she had been shot, so they were frantically leaving the driveway.”
The cars soon fled, desperately searching for cell service, a challenge amid the rolling hills and sparse populations of Washington County, which borders Vermont. They finally found a cell signal about five miles away, on a road adjacent to a local cemetery.
Mr. Monahan was initially uncooperative when police arrived, according to Sheriff Murphy, who said that Mr. Monahan had refused to speak with investigators and “obtained a lawyer that night before he came out of the house.”
But Mr. Monahan’s lawyer, Kurt Mausert, disputed the sheriff’s account of the shooting, saying on Tuesday that the vehicles were speeding up the driveway, with engines revving and lights shining, which “certainly caused some level of alarm to an elderly gentleman who had an elderly wife.”
“Is that a fear-inducing scenario? Well maybe it is,” Mr. Mausert said. “It is not the simple scenario of these people took a wrong turn and within 20 seconds of them taking the wrong turn, this guy’s on his deck blasting away. That’s not what happened.”
Mr. Mausert added that Mr. Monahan “sincerely regrets this tragedy” and “feels terrible that there was a fatality,” but he scolded the sheriff for “basically acting as judge, jury and executioner.”
“When there’s a tragedy and a victim, everyone wants a villain,” he said. “But sometimes they’re just tragedies and victims and there are no villains. And this is one of those times.”
In an interview, Sheriff Murphy said that Ms. Gillis — a former competitive cheerleader, honor student and budding artist — was “a beautiful and kind soul” who had hoped to study marine biology.
“It’s just a tragic situation,” he said.
Albert Weils, a neighbor who lives three doors down from the Gillis family home in Schuylerville, about 25 miles southwest of Hebron, said that Ms. Gillis’s father, Andy Gillis, is a correction officer at Washington County Correctional Facility.
“We don’t think of stuff happening like that around here,” Mr. Weils said, adding, “It’s a total shame.”
The family was largely quiet on Tuesday, and Ms. Gillis’s grandfather’s, Jack Amodeo, said that they were huddled, trying to process the shooting. “It’s really brought us down to our knees,” he said.
Friends of the victim said that she and others may have been headed to a party held by other Schuylerville graduates when they went up the wrong driveway. “There was friends from this community who were at that party,” said Dallas Salls, who was a friend and works in a pizza place near the high school.
Her sister, Victoria Salls, 20, a close friend who was also a former downstairs neighbor in Schuylerville, said that Ms. Gillis was “the glue to her family.” She said that the shooting had made her and others scared to show up at someone’s door or pull into the wrong driveway.
And while she said she saw parallels with the Kansas City case, Ms. Salls noted that Ralph Yarl had somehow survived. Ms. Gillis, she said, is “never going to come home. She’s never going to see her sisters. She’s never going to be able to watch them grow up.”
In Hebron, a town of about 1,800 people about 60 miles northeast of Albany, several residents recalled Mr. Monahan as a dyspeptic and sometimes combative personality.
Mr. Matthews said that Mr. Monahan could be intimidating, striking a “righteous” attitude, and recalled an incident where a local church had put up floodlights over a basketball court thousands of feet from his home.
But, he said, Mr. Monahan — whose home has a porch and floor-to-ceiling windows with a commanding view of the valley, and the church, below — suspected something sinister.
“He felt that they had done it intentionally,” Mr. Matthews said. “This is the church, you know? It’s not like somebody set a spotlight up to highlight his house.”
Brian Campbell, the town supervisor, said in a blogpost that the shooting had deeply affected his “very quiet and tranquil town.”
He added: “I can’t even fathom what would make a person shoot at a car that was in their driveway if they didn’t even know the people in the car.”