An armed 18-year-old girl "infatuated" with the Columbine school massacre was found dead after fears she was seeking to replicate the shooting 20 years on.
Sol Pais, a high school pupil, made threats online and then flew from her home in Miami Beach, Florida to Denver, Colorado, where Columbine is located.
She then bought a pump-action shotgun and ammunition and was seen near the school wearing camouflage trousers, black boots and a black T-shirt.
Columbine and more than 20 other schools in the Denver area were closed on Wednesday, with 500,000 pupils staying at home as the FBI and police searched for her.
She was later found dead from what police called an "apparent self-inflicted gunshot wound" in woodland near a camp ground 60 miles southwest of Denver.
Police, including a SWAT team, had flooded into the area after hikers reported seeing a naked woman with a gun running through the woods".
An FBI spokesman said: "There is no longer a threat to the community."
On April 20,1999 two heavily armed teenage gunmen – Eric Harris and Dylan Klebold – killed 12 fellow pupils and a teacher before taking their own lives.
It set off an era of mass shootings in American schools and other public venues.
Police said Pais had "made threats to commit an act of violence" in the Denver area, and had written "deeply disturbed" posts on the internet. She had been "infatuated with the perpetrators of Columbine".
She sought advice online on how to buy a gun in Colorado, which she did at a gun shop near Columbine.
Local sheriff Jeff Shrader said: "The firearm was purchased legally. I’m sure there will be some ongoing evaluation in that regard."
During the massive search police declared her "armed and extremely dangerous".
Jared Polis, the Colorado governor, said there had been "a lot of anxiety".
Peter Langman, an expert on the psychology of school shooters, said more than 30 other attacks, from California to Germany, have been inspired in some manner by Columbine.