In Colorado, schools across 20 districts in the Denver area are closed today as authorities hunt for a woman they say is “infatuated” with the Columbine massacre and traveled to Denver Monday. Eighteen-year-old Sol Pais reportedly bought a gun and ammunition after arriving in Denver and made threats that the FBI say are “credible” but nonspecific. Denver area schools, including Columbine High School, increased security Tuesday after the news broke. The 20th anniversary of the mass shooting at Columbine High—in which two students killed 12 fellow students and one teacher—is this Saturday, April 20.