AUDIE CORNISH, HOST:
Tomorrow marks 20 years since two gunmen at Columbine High School in Colorado killed 13 people. The incident is still relevant today. This week, the FBI says a woman infatuated with Columbine made credible threats, traveled to the area and bought a gun. From member station KUNC, Leigh Paterson reports that, for the last two decades, schools have taken steps to better protect and care for their students.