Washington Navy Yard shooting

The Washington Navy Yard shooting occurred on September 16, 2013, when 34-year-old Aaron Alexis fatally shot 12 people and injured three others in a mass shooting at the headquarters of the Naval Sea Systems Command (NAVSEA) inside the Washington Navy Yard in southeast Washington, D.C. The attack took place in the Navy Yard's Building 197; it began around 8:16 a.m. EDT and ended when police killed Alexis around 9:25 a.m. It is the deadliest mass shooting in Washington, D.C. history, as well as the second deadliest mass murder on a U.S. military base, behind the 2009 Fort Hood shooting.

Alexis left a Residence Inn Hotel he was booked into on Monday, September 16 and arrived at the Navy Yard in a rented Toyota Prius at around 7:53 a.m., using a valid pass to enter the Yard.

As shown on surveillance footage, he entered Building 197 at 8:08 a.m. through the main entrance, carrying a disassembled shotgun (its barrel and stock had been sawed off) in a shoulder bag.

He went to the fourth floor, where he had conducted work during the prior week.

There, he assembled the shotgun inside a bathroom, then emerged and crossed a hallway into the Building's 4 West area, a cubicle area near the atrium.

He began shooting at 8:16 a.m. Six people were hit, five of whom died; the sixth survived wounds to the head and hand.

At 8:17 a.m., the first 9-1-1 calls were made.

By 8:20 a.m., Alexis had shot and killed eight people on the fourth floor, and he made his way to the third floor, where he fatally shot two more people within the next two minutes.

He also fired at several people on at least five separate occasions, wounding one woman in the shoulder as she ran up a stairwell.

A NAVSEA employee described encountering a gunman wearing all-blue clothing in a third-floor hallway and said that "he just turned and started firing."

After firing several shots on the third floor, Alexis went to the first floor.

Officers began arriving at 8:23 a.m. from the D.C. Metropolitan Police Department and several other law enforcement agencies.

There are many buildings on the base, however, and officers were unable to discern Building 197's location, so they asked bystanders where it was.

They eventually found Building 197 after moving towards the direction from which people were fleeing.

There was confusion regarding the shooting also taking place in a nearby building; in reality, a wounded victim had been evacuated from Building 197 and moved to an area near the second building for medical attention.

The United States Capitol Police became embroiled in a controversy when the police union accused the agency of ordering its personnel to stand down and not respond to the shooting.

While on the first floor, the shooter moved around randomly before turning around and heading towards the front entrance.

He shot and killed Richard Ridgell, the security officer stationed there, and took his 9mm Beretta M9 pistol.

Two police officers had asked Ridgell to remain at his post and try to stop the gunman if he attempted to leave the building.

The shooter then fired his shotgun at a second security guard and a Navy military police officer at the first-floor atrium, missing both; the security guard fired back and the shooter fled down a hallway.

Shortly afterwards, the shooter fired at two police officers and a Naval Criminal Investigative Service agent in another hallway before fleeing again.

At 8:34 a.m., the shooter went towards the west side of the building, where he encountered two men standing at a corner of the building in an alleyway.

He tried to fire at them with his shotgun but realized that he was out of ammunition; he switched to the Beretta, killing one of the men, and the other man escaped without injury.

Reports indicated that the victim in the alleyway was hit by a "stray bullet".

The shooter's use of the pistol in the alleyway led police to initially believe that a second gunman was involved.

After killing his final victim, Alexis moved to a cubicle area where he discarded the shotgun.

At the same time, a team of officers entered Building 197, but they became confused after gunshots echoed through the atrium, leading them to believe that he was on an upper floor.

They headed up to the second floor while Alexis remained on the first floor.

At approximately 8:55 a.m., he went to the third floor and concealed himself inside a bank of cubicles.

At 9:12 a.m., two officers and two NCIS agents entered the cubicle area and Alexis opened fire on them, hitting officer Scott Williams in both legs.

Officer Emmanuel Smith and NCIS agents Brian Kelley and Ed Martin dragged Williams out of the area and alerted other officers to the shooter's presence.

Williams was later taken down to the first floor for medical attention, recovering from his wounds.

At 9:15 a.m., D.C. Police Emergency Response Team officer Dorian DeSantis and U.S. Park Police officers Andrew Wong and Carl Hiott entered the cubicle area and searched the individual banks.

Eventually, Alexis jumped out from one of the desks and fired at DeSantis from approximately 5 ft away, hitting him twice in his tactical vest, and the three officers returned fire.

DeSantis was uninjured by the gunshot.

At 9:25 a.m., DeSantis shot Alexis in the head, and his death was confirmed at 11:50 a.m.

There were 13 fatalities, including Alexis.

He and 11 of the victims were killed at the scene, while Vishnu Pandit, a program manager in the US Navy, later died at George Washington University Hospital.

All the victims were civilian employees or contractors, none of them in the military.

Eight others were injured, three of them from gunfire.