A Florida student who officials said was on a “pilgrimage” to Columbine near the 20th anniversary of the shooting was found dead on Wednesday. Her threats had prompted a massive police hunt in the Denver area and the closing of hundreds of schools.

Sheriff Jeff Shrader of Jefferson County, Colo., said the woman, identified as Sol Pais, 18, was found dead from an “apparent self-inflicted gunshot wound.”

Before she was found, the authorities said Ms. Pais had traveled to Denver and was considered armed and “extremely dangerous,” leading to the decision to keep about half a million students home in two dozen school districts.

An F.B.I. bulletin sent to local law enforcement agencies on Tuesday said Ms. Pais was “infatuated” with the Columbine attack, and officials expressed concerns about her mental stability. She had also purchased a shotgun and ammunition after arriving in Denver, the authorities said.

Ms. Pais, a student at Miami Beach Senior High School, had last been seen wearing a black T-shirt, camouflage pants and black boots, the authorities said.

Sheriff Shrader said it did not appear that she had any help from friends in the area, just a fascination with the Columbine area and the horrendous crime that took place there 20 years ago.

He said that he did not believe that law enforcement officials were “in active pursuit at the time she was found dead.”

Officials knew immediately that the threat was serious, said John McDonald, the school safety executive director of Jefferson County. “The shadow of Columbine looms pretty large,” Mr. McDonald said. “We are used to threats certainly at Columbine. This one felt different.”

Law enforcement officials were worried by Ms. Pais’s determination: She bought a plane ticket, made the journey and bought a gun, he said. Mr. McDonald called it a “pilgrimage.”

When she bought the gun at a shop in Littleton, near Columbine, that raised the threat, officials said.

The decision to close schools across the area was made when they realized that Ms. Pais was moving over a wide area, from the airport, to Littleton to the foothills of the mountains. They suggested that she had used Uber to get around.

But officials said they had been making contingency plans to reopen the schools in case the threat continued, even if that meant overcoming logistical hurdles such as sources of transportation and food service. “We did not wish to have one person hold all of the schools in the front range of the whole state hostage,” said Jason Glass, the superintendent of Jefferson County Public Schools. Mr. Glass said that even though those plans had not been carried out, they would be saved for the future.

Mr. McDonald, the school safety director, said the system did not want to play into the fascination with Columbine. “We’re not a place to come visit if you’re not a student,” Mr. McDonald said. “We’re not a tourist attraction. We’re not a place for you to come and gain inspiration.”

Ms. Pais’ parents reported her missing to police in Surfside, Fla., on Monday. Officers there alerted Miami Beach Police, where Ms. Pais went to school. Investigators there found alarming social media posts apparently written by Ms. Pais and contacted federal law enforcement, Miami Beach Mayor Dan Gelber said.

[Here is what we know about Sol Pais]

Daisy Gonzalez-Diego, a spokeswoman for the Miami-Dade County Public Schools, confirmed on Wednesday that Ms. Pais was a student at Miami Beach Senior High School. The school district was assisting the F.B.I. with its investigation, Ms. Gonzalez-Diego said.

The F.B.I. said that Ms. Pais had arrived at the Denver airport and bought a pump-action shotgun and ammunition at a store. “She was then taken to an area where she was last seen out toward the foothills,” Mr. Phillips said.

Law enforcement officers outside Columbine High School on Wednesday. Schools in the area were closed as the hunt for Ms. Pais was underway.CreditDaniel Brenner for The New York Times

“Because of her comments and her actions, because of her travel here to the state, because of her procurement of a weapon immediately upon arriving here,” he added. “We consider her to be a credible threat — certainly to the community and, potentially, to schools,” he said.

The search for Ms. Pais quickly upended families across the Denver region. Thousands of parents woke on Wednesday morning to discover that schools had been canceled and that they would have to explain the cancellation to their children.

For some of the youngest students, this was their first introduction to the Columbine shooting, and to its legacy.

Some parents decided that they would keep their children inside all day; others said this would effectively hand Ms. Pais a victory.

“It’s sad and scary,” said Jeff Desserich, a math teacher at a charter school in Denver, who spent the morning trying to explain to his daughters Anais, 8, and Elena, 6, why they would not be going to class.

“I said, ‘There is a lady, she probably has some sort of mental health issue,’” he said, “And I talked a little about the sad events of Columbine and how her flying to Denver and buying a weapon, that’s a really big flag for law enforcement.”

Just last Friday, Colorado’s Democratic governor signed a “red flag” law that would allow guns to be temporarily seized from people deemed to be dangerous to themselves or others. The act was bitterly opposed by more than a dozen sheriffs and officials from largely rural, conservative counties who vowed not to enforce it.

The state also passed significant gun control measures in 2013 that expanded background checks, but despite that, Colorado does not have a specific waiting period for someone who wants to buy a gun.

In Florida, The Miami Herald reported that a man who answered the door at Ms. Pais’s address on Tuesday identified himself as her father and said he had lost contact with her on Sunday. “I think maybe she’s got a mental problem,” he told The Herald. “I think she’s going to be O.K.”

In Colorado, the announcement prompted “lockouts,” or heightened security measures, at schools in Jefferson County and the surrounding area on Tuesday. During a lockout, all exterior doors are locked at a school but business continues as usual inside. Police officers aided in end-of-day student release. County officials said that all students and staff members were safe.

It was not the first threat for students at Columbine High School. In December, an anonymous caller claimed bombs had been planted inside the school. The police responded, but the threat proved to be a hoax.

During the Columbine High School shooting on April 20, 1999, two students shot and killed 12 of their classmates and a teacher.

The shooting’s aftermath was widely televised, and young people across America continue to be influenced by the symbology of the Columbine shooting and the students who carried it out, according to law enforcement officials, researchers and educators.

In May 2018, a 17-year-old junior in Santa Fe, Tex., shot his teachers and fellow students with a sawed-off shotgun while wearing a black trench coat and carrying Molotov cocktails, his arsenal and attire inspired by the Columbine gunmen. The 20-year-old attacker who killed 26 people at Sandy Hook Elementary School in Connecticut in 2012 had compiled materials on the Columbine attackers on his computer. And in his manifesto, the 23-year-old student who shot and killed 32 people at Virginia Tech in 2007 had called the Columbine gunmen by their first names and described them as “we martyrs.”

The killers have achieved dark folk hero status in the corners of the internet where their carefully planned massacre is remembered, studied and in some cases even celebrated, officials say. Their admirers, often known as “Columbiners,” are frequently depressed, alienated or mentally disturbed, drawn to the Columbine subculture because they see it as a way to lash out at the world and to get the attention of a society that they believe bullies, ignores or misunderstands them.

Jefferson County, home to Columbine High School, has spent the past 20 years grappling with that legacy.

Students, teachers, families and law enforcement officers have had to deal not only with the emotional trauma of the shooting, but also with the people who have become obsessed with it and the copycats who have carried out their own attacks.

In an interview last year, the head of safety for Jefferson County schools, John McDonald, said he had often apprehended people who came from around the country to try to enter the school, a major safety concern. These visits — and interest in the shooting — have only increased over time, he said: “I’ve been dealing with this for more than a decade, and it’s never been more of an issue than it is now, 20 years later.”

Source: Nytimes.com