Law enforcement agents involved in the fatal shooting of 34-year-old Defense Department contractor Aaron Alexis acted in defense of themselves and others, prosecutors said in a statement released nearly a year after the day when 12 civilians were killed and four other people were wounded, including a Metropolitan Police Department officer.  

“After a careful review of the evidence, we have closed this investigation,” Machen said. “We concluded that the law enforcement officers involved demonstrated exceptional valor in acting to protect the lives of Navy Yard employees and other responding law enforcement officers.” Response to the deadly shooting in Southeast Washington on Sept. 16, 2013, involved officers from multiple departments, including an elite, heavily armed team of Capitol Police. Those four officers were recalled from the scene by commanders, because of concerns about potential threat to the Capitol, according to a controversial internal review released in November.  

The review by the U.S. Attorney’s office included witness statements, surveillance video, photographs, diagrams, physical evidence and law enforcement agency reports from the FBI, Metropolitan Police Department, U.S. Park Police, and Naval Criminal Investigative Service, and the autopsy report for Alexis. It found that none of the law enforcement officers possessed the requisite criminal intent, and that officers acted reasonably at all times to “neutralize a life-threatening situation.”  

Wednesday’s announcement included a detailed play-by-play of the shootout.  

Shortly after 8 a.m., Alexis entered Building 197 on the west side of the Navy Yard complex. Within the next 15 minutes, Alexis, who was armed with a 12-gauge sawed-off shotgun, systematically moved from floor to floor, killing and wounding anyone he saw. According to the review:

Eight victims were shot and killed on the fourth floor; two others were shot and wounded. Two victims were killed on the third floor; two other victims, including an MPD officer, were shot and wounded. One victim, a building security officer, was killed on the first floor; and one victim was killed in a parking area. After killing the building security officer, Mr. Alexis took the officer’s 9-millimeter handgun, which he also used as a weapon.

After killing the victims in rapid succession, Mr. Alexis kept moving through the building’s stairwells, hallways, and work areas and cubicles, repeatedly firing at law enforcement and security officers trying to apprehend him. He shot at a second building security officer and a U.S. Navy Military Police officer on the first floor, leading to an exchange of gunfire. The building security officer fired at Mr. Alexis as Mr. Alexis ran across the atrium and out of view. In a separate confrontation, Mr. Alexis fired at an NCIS agent and two officers with the Naval District of Washington, also on the first floor. They returned fire; however, there is no evidence that Mr. Alexis was hit by this gunfire.

Mr. Alexis then returned to the third floor and once again confronted police, shooting a Special Operations Division officer from the MPD, who collapsed to the floor. Another NCIS agent fired back at Mr. Alexis after the officer was hit, but Mr. Alexis was not hit.

Finally, after these shootings, Mr. Alexis hid under a desk on the third floor, waited, and attempted to ambush an Emergency Response Team officer from the MPD and a U.S. Park Police officer as they entered the area where he was located. At about 9:25 a.m., Mr. Alexis shot at the MPD Emergency Response Team officer, hitting the plate of his police tactical vest. The MPD Emergency Response Team officer and the U.S. Park Police officer returned fire and were able to shoot and kill Mr. Alexis.