Post 9/11 veterans and mass violence

July 17, 2016: Gavin Long, 29, a former Marine and Iraq war veteran, killed three law enforcement officers in Louisiana.

July 7, 2016: Micah Johnson, 25, an Army veteran who had served in Afghanistan, ambushed and killed five white police officers in Dallas in what was described as a racially motivated attack.

May 29, 2016: Army veteran Dionisio Garza III, 25, of Rancho Cucamonga, killed one person and injured several others in a shooting rampage at a Houston auto detail shop before being killed by a SWAT officer. Garza spent four years in the Army, receiving his discharge in 2014.

April 2, 2014: 34-year-old Army Specialist Ivan Lopez, an Iraq war veteran being evaluated for post-traumatic stress disorder, opened fire at Fort Hood, killing three people and wounding 16 before killing himself.

Sept. 17, 2013: Aaron Alexis, 34, a civilian defense contractor, went on a shooting rampage inside a building at the heavily secured Washington Navy Yard, killing 12 people before he was slain in a running shootout with police. Alexis served as a full-time Navy reservist between 2007 and 2011.

March 11, 2012: Sixteen Afghan villagers, including nine children, were killed during a predawn attack. U.S. Army Staff Sgt. Robert Bales pleaded guilty in a deal to avoid the death penalty and was sentenced Aug. 23, 2013, to life in prison with no chance of parole. Bales never explained why he armed himself with a 9 mm pistol and an M-4 rifle and left his post on the killing mission.

Nov. 5, 2009: Maj. Nidal Malik Hasan, 39, a U.S. Army psychiatrist, killed 13 when he went on a rampage at Fort Hood, Texas. Hasan, 39, was convicted in August for killing 13 people. He told the court he was performing jihad.