CHATTANOOGA, Tenn. - Counterterrorism investigators are trying to figure out why a 24-year-old Kuwait-born man who seemingly had a typical suburban American upbringing attacked two U.S. military sites in a shooting rampage that left four Marines dead. Muhammad Youssef Abdulazeez of Hixson, Tennessee, did not appear to have been on the radar of federal authorities before the bloodshed Thursday, officials said, and they were still searching for a motive.