BOZEMAN, Mont. — Hours before the snow began falling in a sudden autumn blizzard, three siblings gathered beneath the tall pines of the city cemetery. They were there to bury their little brother, the final victim of a murderous rampage that more than three decades earlier claimed their parents and grandmother.

The killer had been a stranger, a 16-year-old boy who lived a house away in the eastern Montana town of Glendive. On a frigid midnight just days before Thanksgiving, he showed up at their front door, barged in and started firing.

It’s difficult today, in an era of gun violence and mass shootings, to grasp how much his crime shocked an entire state and shattered two communities hundreds of miles apart. In 1987, Montana was a relatively safe, far-flung web of small cities and towns, with less than a million people total. It was a place where families routinely left their doors unlocked. That began to change.

The killer would go on to become the most prolific murderer in modern Montana history before hanging himself in prison. The 9-year-old boy he attacked would survive, though with a brain injury and severe psychological trauma that ultimately proved inescapable.

Sean Brooks died in late summer after years of running from the demons of that night. He was, until the end, a jokester, a charmer, an unflagging friend to the homeless, animals and just about anyone down on their luck. He’d moved far away from Montana and, for a time, had a job he loved and a partner who made him smile.

Yet, as his brother and two sisters stood graveside, that period of calm seemed like a fleeting, illusory moment. For them and the other relatives and friends at the cemetery, Sean’s death underscored how such violence reverberates for a lifetime.

“He never had a chance,” said Helen Wilson, the family friend who helped raise him in the tragedy’s aftermath.

Jim and Sharon Brooks had not wanted to move their family to Glendive. It was nearly five hours away, almost to the North Dakota border, but when the Burlington Northern Railroad shuttered its machine shops in Livingston and eliminated 300 jobs overnight, their town splintered. Jim, a machinist, was at least offered a transfer, though the place they were going had little in common with the place they were leaving beyond a railroad line and the Yellowstone River.

They’d try to make the best of it. “They didn’t have a choice,” recalled Mike Brooks, who was then a high school senior.

One bright spot was the house they found, a rancher with spacious bedrooms and a sprawling basement on the edge of town. It had a big yard for Sean and Sherri and plenty of room for Mike and Sami, the oldest, to stay when they came home on breaks from college.

By fall 1987, 14-year-old Sherri was fast becoming a basketball star. She was a starter on the Glendive Red Devils girls’ team, and on the evening of Nov. 19, she was playing in a regional tournament, her parents and grandmother in the stands cheering. After the game, she decided to hang out with friends to celebrate the team’s victory. The rest of the family headed home. Both Mike and Sami were away at school.

About the same time, a sullen youth with deep-set eyes and a thick mullet haircut was at a party getting drunk on Southern Comfort. Doug Turner had recently been released from a juvenile alcohol treatment program and was reportedly mouthing off to whomever would listen about how he was going to kill someone that night. No one took him seriously.

He showed up at the Brooks house around midnight, a stranger armed with a rifle. The family was waiting for Sherri, the door unlocked. Turner struggled with Jim Brooks at the door and shot him dead in the living room. He then moved through the house and shot the two women. Sharon stumbled into the street.

Sean and a friend had been playing in the basement and ran upstairs when they heard the noise. The teenager aimed at both boys, but his gun misfired, so he clubbed them with the rifle butt. When Turner finally wandered away, Sean ran outside and found his dying mother. A neighbor driving by pulled him into her car and called the police.

At that point, the Brooks family had lived in Glendive for just over two years.

The town has not aged well in the decades since. Its population has fallen nearly 20 percent, part of a long, slow exodus from family farms and rail transport in this part of the country. Much of downtown is in tatters, belying the signs in store windows that proclaim: “I believe in Glendive.”

In the Highland Park subdivision, the Brooks family’s former house calls little attention to itself. A tall fence shields the front yard. The house where the family’s killer lived, an empty lot away, also remains standing. His mother, who could not be reached for comment, still lives in town.

Turner wasn’t the first violent teen to make the news in Montana during the 1980s. A couple of years earlier, two boys in Butte, aged 14 and 15, had killed their mothers and a sister not far from their junior high school. Under state law at the time, the pair could not be tried as adults. They were sent to a reform school and released at 21, their records sealed. The boys’ stay overlapped with the several months that Turner spent at the facility for drug-related crimes.

It’s impossible to know whether the trio interacted but is equally impossible that Turner didn’t know about the other two and what they had done. One thing is certain, though: Their crime altered his life. The Montana legislature revised the law because of it, which meant that, at 16, Turner could be tried and sentenced as an adult for triple homicide.

He would kill six more people while in prison, then hang himself with a bedsheet in his cell on death row. In 16 years, he never gave a reason for what he did to the Brooks family. He never even admitted to remembering it.

Over the years, Sean’s big brother kept a thick, weathered manila envelope unopened. A packet of dozens of newspaper clippings, sent by a relative, retold the public version of his family’s private anguish. In the final weeks of Sean’s life, Mike Brooks finally opened the envelope, scanning the yellowed pages and creased photographs and realizing for the first time what the rest of the state and the nation beyond was told about their ordeal.

Forgetting was better for so many years, he says, because the family felt so stigmatized.

“We couldn’t even go to the mall in Bozeman without people pointing and whispering,” he said.

He learned little new from the old stories, but he and his sisters rediscovered painful images that had been offered up for all to see.

One front-page photo showed the chalk outline of their mother’s body in the street in front of their home. Another was a close-up portrait of family members on their way into the funeral: Mike, 19, in visible anguish; Sherri 14, sad but stoic; their grandfather, his face twisted by the pain of losing his wife and only child. His youngest grandchild, pulled close beside him, stares hard at the ground. A small shaved spot on Sean’s head marked where he’d been hit and needed stitches. For the rest of his life, his strawberry-blond hair never grew back there.

They all coped, and tried to move on, in different ways.

The tragedy freed Mike from an ongoing struggle over how to tell his family that he was gay. His parents’ deaths devastated him but persuaded him to live his life. He moved to more liberal Missoula to finish college, began dating men and eventually met his husband.

Sami was halfway through college in Bozeman and early in a relationship with the man she later would marry. She was the motherly sister, and her mission would become caring for her little brother.

Sherri focused on basketball. Her parents and grandparents had been unfailingly proud of her athletic prowess, and playing well felt like a tribute to their memories. “Basketball saved my life,” she explained through tears at the cemetery.

Then there was Sean. He stayed with Sami after the murder until he was 15, about the time he discovered that alcohol soothed his anxiety. He moved back to Livingston and got through high school and college. He and his siblings remained close but didn’t speak much about the murders. If something was mentioned, he’d leave the room.

“I can’t imagine what he went through, seeing what he saw that night, the way he changed,” said Rusty Shipman, a friend of the Brooks kids in Livingston. “There’s not a day that goes by that I don’t think of this family and what happened to them.”

For the three older children who weren’t home that night, the trauma became a kind of background noise. For Sean, the trauma never really receded. He didn’t like being alone anywhere. Even as an adult, he wore his father’s class ring and kept a fading photo in his wallet. It showed him as a toddler, smiling atop his mother’s lap.

Booze killed him in the end. He drank more and more over the years, leading to more falls, more head injuries, strained friendships, broken relationships. Rehab never worked; his siblings took care of his bills, his housing, his practical matters, but they couldn’t reach in deep enough to pull him out. In his 30s, Sean moved near his brother in Arizona. There he found work and love, only to crash hard when his partner died suddenly and he lost his job.

Not quite two years ago, he learned his liver was failing. A transplant might have saved him, but the operation was impossible if he kept drinking. He couldn’t stop.

By early August, he was dying. He was unrecognizable from past photos, his handsome face bloated and distorted because of the toxins his liver was unable to filter. He was mostly incoherent. A sometime friend was staying with him, using his debit card to buy him food and Mike’s Hard Lemonade.

Within a week, his siblings moved Sean into hospice. He died Aug. 19, with all of them at his bedside. He was 41.

“It’s so painful, even after 30-some years,” admitted Sami, who still deals with anxiety that someone she’s close to will die suddenly. “It’s one thing after another with our family. It’s just a constant reminder of the loss.”

She, Mike and Sherri brought Sean’s ashes home to Montana and buried half with his parents, placing an elegant blue urn in their plot.

The rest of his remains, they gave to the grand sweep of the Yellowstone River.