More than a dozen school districts in the Denver area have abruptly cancelled classes today amid what police are calling a "credible threat."
Law enforcement is looking for Sol Pais, an 18-year old Florida woman who is said to be armed, dangerous, and obsessed with the Columbine massacre.
Jefferson County Sheriff Jeff Shrader says they can't discount the potential danger:
"We take these threats seriously. It's certainly not the first threat that we've had that involves Columbine High School, or references it."
Dean Philips with the FBI in Denver says the woman managed to buy a weapon as soon as she arrived in Colorado. He adds that investigators can't say for certain she may target Columbine, and there is concern:
"She has had an infatuation with Columbine and the perpetrators of Columbine; she's made comments to that effect. But she hasn't identified a specific threat to a specific school."
Complicating the case is the fact the suspect has not technically committed a crime.
The 20th anniversary of the mass shooting that left 12 students and a teacher dead is Saturday.