Aaron Alexis seems a study in contradictions: a former Navy reservist, a Defense Department contractor, a convert to Buddhism who was taking an online course in aeronautics. But he also had flashes of temper that led to run-ins with police over shootings in Fort Worth, Texas, and Seattle. A profile began to emerge of the man authorities identified as the gunman in Monday's mass shooting at the Navy Yard in Washington, D.C., that left 13 people dead, including the 34-year-old man. While some neighbors and acquaintances described him as "nice," his father once told detectives in Seattle his son had anger management problems related to post-traumatic stress brought on by the terrorist attacks of Sept. 11, 2001. He also complained about the Navy and being a victim of discrimination. Police in Seattle say Alexis was arrested there in 2004 for shooting out the tires of another man's vehicle in what he described to detectives as an anger-fueled "blackout."