Memphis police say National Guard troops fired their weapons in the early morning hours Sunday, killing a man who was armed with a handgun. Police say officers were responding to calls of shots fired in downtown Memphis just before 4 am local time when they saw "an armed male carrying a handgun." The man — identified by the Tennessee Bureau of Investigation as 20-year-old Tyrin Johnson — fled on foot, pursued by Memphis police officers along with Tennessee National Guard soldiers who are assigned to the area. What happened next was not immediately clear. "For reasons under investigation, the situation...