He said he had no other information. 'We will have extra safety and security staff on site at all schools affected, ' Jefferson County Public Schools said.
The Aurora Police Department said it was "taking this threat seriously" and that it was working with Aurora Public Schools and Cherry Creek Schools. They called her "extremely risky".
All schools in the Denver area are being urged to tighten security after what appears to be a credible threat caused a lockout at Columbine High School and more than 20 other schools in the area.
No students were injured, and the lockdown was a precaution recommended by the Colorado Department of Education. As the district prepares for the day's memorial events, it is fending off an onslaught of curious strangers who trespass in the parking lot of the high school - sometimes more than 30 people in a single day.
An 18-year-old Florida woman "infatuated" with the Columbine school shooting traveled to Colorado by plane Monday, purchased a shotgun and ammunition in Littleton and disappeared into the foothills of Jefferson County. She is about 5-foot-5 and was last seen wearing a black T-shirt, camouflage trousers and black boots, authorities said.
"If we found her tonight, we will certainly hold her for as long as we can legally", Phillips said.
Officials are now seeking 18-year-old Sol Pais from florida in connection with the threat said to be armed and risky, and "infatuated" with Columbine.
Police say they received a "credible threat", but, the threat did not name a specific school. The students walked to crosswalks and buses parked near the entrance. Columbine High School is in Jefferson County. The FBI is leading the investigation in Jefferson County, Fulton said.
In a Tuesday night press conference, Phillips said Pais expressed an "infatuation with Columbine" and the two teenage gunmen who perpetuated the shooting in past comments.
"It's certainly not the first threat that we've had that involves Columbine High School, or references it.
And in that regard, I know that this opens a wound, especially on this anniversary week, for those families who were most deeply impacted by this", Jefferson County Sheriff Jeff Shrader said.
School officials say the doors were locked but classes were continuing at Columbine and two other nearby schools and at other schools farther away in the same district. There was no immediate indication whether there was any connection to the anniversary.
In the years since the massacre, the shooting has become a grim obsession for people known as "Columbiners".