San Antonio Police Chief William McManus answers questions from the media, May 3, 2016, in San Antonio, Texas. (Bob Owen/The San Antonio Express-News via AP, File) HOUSTON — A Texas mother has been charged with a terrorism-related crime after being accused of buying her 13-year-old son ammunition and tactical gear as he allegedly planned mass violence at his middle school, authorities said Thursday. The boy, who was also charged with terrorism, had shown up to the school this week wearing a mask and tactical gear but left shortly after, according to San Antonio police. He was later detained off campus....