LITTLETON, Colo. (AP) — A Florida teenager who authorities say was obsessed with the Columbine school shooting and may have been planning an attack in Colorado just ahead of the 20th anniversary was found dead Wednesday in an apparent suicide after a nearly 24-hour manhunt.

The body of 18-year-old high schooler Sol Pais was discovered in the mountains outside Denver with what appeared to be a self-inflicted gunshot wound after investigators got a tip from the driver who took her there, the FBI said.

During the manhunt, Denver-area schools closed as a precaution, with classes and extracurricula...