WASHINGTON A gunman killed a dozen people as the workday began at the Washington Navy Yard on Monday, creating an improbable moment of horror at a military facility with armed guards at every gate and leaving investigators seeking clues about what spurred the attack.
Aaron Alexis received a general discharge in 2011 from the Navy Reserve, a designation that usually signals a problem in his record. Alexis was arrested but not charged in a gun incident in Seattle in 2004 but still had a security clearance with a military contractor that would have allowed him access to the Navy Yard, officials said.
The suspect died when his mayhem ended in a fierce gun battle with police. Authorities did not release the names of the victims, and many family members were still awaiting word about loved ones.
The shootings constituted the worst loss of life in a single incident in the region since the 2001 attacks on the Pentagon killed at least 184 people.
This is yet another heartbreak for our city, said Del. Eleanor Holmes Norton, D-D.C.
Alexis left Texas about a year ago, and authorities made a public appeal Monday for help in tracing his movements since then. They said they believe he had been in the Washington region for about four months working as an hourly employee with a defense contractor.
We dont know what the motive is, said D.C. Mayor Vincent Gray.
The mayor said there was no reason to suspect terrorism. Other officials said they do not know whether Alexiss discharge played a role in the shooting but said that is one line of inquiry.
The shooting began about 8:15 a.m. when the echo of gunfire behind the walled security of a military base stunned people arriving to begin their workweek.
I didnt believe it, said Alley Gibson, 28, who works in Building 197, where the shooting took place. At first I was in shock. Nothing like this ever happens especially not on a base. Its just not normal. Its wild its like a movie.
As people scattered for cover, they turned to text messages and office televisions in an effort to determine what was going on.
We were sort of in the dark, said John Norquist, 52, a Fairfax, Va., lawyer who served as a civilian adviser in Afghanistan last year. We were trained in active shooter scenarios.
The full weight of Washingtons vast anti-terrorism network converged on Southeast Washington within minutes of the first shots as local and federal law enforcement teamed to sweep the Navy Yard and the neighborhood along the Anacostia River.
The shootings threw the nations capital into turmoil, with police fearful that two other gunmen might be on the loose. But late Monday D.C. Police Chief Cathy Lanier said authorities were confident there was only a lone gunman responsible.
Throughout the day, people were warned to remain in their homes and those at offices on the naval base and in the surrounding neighborhood were told to stay put.
Flights were briefly halted at Reagan National Airport. Schools near the base were locked down. The Senate adjourned early, and people were not allowed to enter or leave much of the Capitol complex.
This has been a dark day, said House Speaker John Boehner, R-Ohio.
The Washington Nationals, whose ballpark is close to the base, were told to stay away from their stadium. A game against the division-leading Atlanta Braves was postponed until Tuesday.
Investigators said Alexis shot a security guard most likely with a shotgun he bought in Lorton in Fairfax County, Va. outside Building 197 at the Navy Yard. He took the guards handgun before moving methodically through the interior, they said, leaving dead bodies and 14 people wounded on at least two floors before he was dead.
Among those injured was a D.C. police officer who was shot twice in the leg. He is expected to survive.
Theres no question he would have kept shooting, said Lanier, who declined to say how many shots were fired from start to finish. Police said they believe that Alexis also obtained an assault rifle once he was in the building, but it was unclear how.
Perplexing to those as the event unfolded around them and puzzling to investigators in the aftermath: How did a man with a shotgun pass through one of three gates where Marine and Navy security personnel screen all visitors?
I dont think we know that, said Valerie Parlave, the assistant FBI director in charge of the D.C. field office. The investigation is still very active.
Several former military officers who work in the building said that there are armed guards at the main entrance and that employees must scan an access card. But two people who work there said those with properly coded cards can enter through a side door from a garage, bypassing the security guards.