U.S. Army via Wikimedia Commons
2009: Maj. Nidal Malik Hasan, a 39-year-old U.S. Army psychiatrist of Palestinian descent, kills 13 and wounds 29 at Fort Hood, located just outside Killeen, Texas, in the deadliest mass shooting at a United States military installation. Hasan was shot and taken into custody by responding officers and is now paralyzed from the waist down. He was eventually convicted on 13 counts of premeditated murder and 32 counts of attempted murder and sentenced to death. Hasan remains imprisoned at the United States Disciplinary Barracks at Fort Leavenworth in Kansas awaiting execution while his case is reviewed by appellate courts.