"There is no longer a threat to the community," the FBI said Wednesday afternoon.
Her body was recovered at Echo Lake campground in the foothills of Mount Evans outside Denver, Colorado.
A website linked to the 18-year-old shows disturbing hand-drawn images of guns, a bloody knife and a skull.
"I feel like a pot of [scalding] water on the verge of boiling over … so dangerously close to spilling over ...." she wrote. "I have done quite a good job at keeping all of the explosive energy inside of me but every time … worse and worse. And worse."
Another website linked to Pais has the headline: "Be the best killer you can be."
Pais was a senior at Miami Beach Senior High School.
A classmate told Inside Edition that she kept to herself and was quiet. Another classmate said she was "by herself a lot."
Pais flew from Florida to Denver on Monday and bought a shotgun and ammo. A "be on the lookout" (BOLO) poster declared she was "infatuated with Columbine School shooting."
Her father, a musician, spoke to a reporter through the door of the family home in Surfside, Florida.
“It's like a bad dream. We don't have any idea,” he said. “Maybe she has a mental problem.”
Twenty school districts in Colorado were closed Wednesday due to the threat.
The Columbine massacre took place 20 years ago this week and Pais' infatuation is shining a spotlight on a bizarre subculture of young people who see Columbine killers Dylan Klebold and Eric Harris as some sort of heroes
They call themselves "Columbiners” and on websites have referenced how much of a “cutie” Harris was.
Dave Cullen, author of the bestseller "Columbine,” spoke to Inside Edition about the latest threats against the schools.
“It is heavily girls and it is becoming more and more girls,” Cullen told Inside Edition about those infatuated with Columbine. “It is kind of a weird thing that has been going on forever. This idealization of a bad boy ... doesn’t get much more bad boy than a mass murderer.”
Frank DiAngelis, the principal of Columbine High School at the time of the massacre, advised Inside Edition on what to pay attention to.
“I tell parents, I tell community members and school officials, if you have students, your kids, that are infatuated with the two gunmen from Columbine high school, that's a red flag,” he said.