Education officials say Denver-area public schools will be closed Wednesday due to an ongoing safety concern as authorities search for a woman whom they say is armed, making threats and “infatuated” with the Columbine High School shooting.

Authorities say 18-year-old Sol Pais made undisclosed threats that prompted Columbine and more than 20 other schools outside Denver to lock their doors for nearly three hours Tuesday afternoon.

Denver Public Schools said all facilities and programs will be closed Wednesday, and there will be no afternoon activities or athletic competitions.

The district said the decision to close campuses was in collaboration with other Denver metro-area school districts.

The Jefferson County Sheriff’s Office and the FBI say Pais traveled to Colorado from Miami on Monday night and bought a pump-action shotgun and ammunition.