WASHINGTON (WFAA/AP) A 34-year-old Fort Worth man is suspected of being one of possibly two shooters in Monday morning's attack at the Washington Navy Yard that left 13 people who died, D.C. police said.
Aaron Alexis was among the 13 killed. A senior law enforcement official said authorities identified the dead gunman through his fingerprints.
Alexis has a criminal history that includes an arrest for a 2010 shooting incident in Fort Worth.
Authorities initially said they were looking for a possible second attacker who may have been disguised in an olive-drab military-style uniform. But as the day wore on and night fell, the rampage increasingly appeared to be the work of a lone gunman.
No motive for the attack the deadliest at a U.S. military installation since Maj. Nidal Hasan's rampage at Fort Hood in 2009 has been established.
Washington Mayor Vincent Gray said there was no indication it was a terrorist attack. But he said the possibility had not been ruled out.
Officials said Alexis may have had a badge that gave him access to the Navy Yard. He was working for a company called 'The Experts,' a subcontractor to Plano-based HP Enterprise Services that refreshed equipment on the Navy Marine Corps Internet network.
A statement from HPsaid the company is 'cooperating fully with law enforcement.'
At an afternoon news conference, Washington Police Chief Cathy Lanier said officers were inside the location seven minutes after gunshots were reported. Alexis returned fire at officers during at least two gun battles. Had authorities not shot him, she said the death toll would have been higher.
'There's no question he would've kept shooting,' Lanier said.
Three weapons were found on the suspect -- an AR-15 assault rifle, a shotgun and a semiautomatic pistol, the official said.
'It's hard to carry that many guns, so there is some thinking that he may have taken some of them from security or whoever else he shot,' the official said.
The FBI is urging anyone with information about Alexis to call 800-225-5324.
He last lived at 7940 White Settlement Road in Fort Worth in December 2010.
Alexis' former roommate Oui Sathamtewakul told News 8's Jim Douglas that he last worked at the Naval Air Station Joint Reserve Base in Fort Worth.The Navy confirmed that Alexis served as a full-time reservist from 2007 to 2011. He left the Navy on January 31, 2011 as a petty officer 3rd class. It's not immediately clear why he left.
Alexis had been working for the Fleet Logistics Support Squadron No. 46 in Fort Worth. The Navy says his home of record was New York City.
Sathamtewakul said Alexis frequently returned home to Fort Worth following travels to other states, like Washington and South Carolina.
The roommate said Alexis was a contractor, and suspected that was why he was in Washington D.C. Sathamtewakul said he was 'shocked' at the allegations; Alexis was a practicing Buddhist and never showed any signs of aggression toward him.
Sathamtewakul said he knew Alexis had a concealed handgun license and that he owned a gun.
Alexis was arrested on September 4, 2010 at his apartment at 2450 Oak Hill Circle when a gun went off in his hands, sending a bullet through the apartment of an upstairs neighbor, public records show.
He told investigators he was cleaning the gun and it went off. The neighbor whose apartment the bullet went through told police that Alexis 'terrified' her and that he confronted her multiple times because of how loud she was in her unit.
The Tarrant County District Attorney's Office issued a statement saying it did not seek to charge Alexis with the crime, a Class A misdemeanor.
'After reviewing the facts presented by the police department, it was determined that the elements constituting recklesness under Texas law were not present and a case was not filed,' the statement said.
The Seattle Police Department said Alexis was arrested in 2004 for shooting out another man's car tires 'in what Alexis later described to detectives as an anger-feueled 'blackout,'' the department wrote in a post on its in-house blog. Quoting from the report:
The victims reported seeing a man, later identified by police as Alexis, walk out of the home next to their worksite, pull a gun from his waistband and fire three shots into the two rear tires of their Honda before he walked slowly back to his home north of the construction site.
Following his arrest, Alexis told detectives he perceived he had been 'mocked' by construction workers the morning of the incident and said they had'disrespected him.' Alexis also claimed he had an anger-fueled 'blackout,' and could not remember firing his gun at the victims' vehicle until an hour after the incident.
Alexis also told police he was present during 'the tragic events of September 11, 2001' and described 'how those events had disturbed him.'
Detectives later spoke with Alexis' father, who lived in New York at the time, who told police Alexis had anger management problems associated with PTSD, and that Alexis had been an active participant in rescue attempts on September 11th, 2001.
Listen to The Fort Worth Star Telegram's Bud Kennedy and Sandy Guerra-Cline talk about Aaron Alexis, who would wait on them at the White Settlement restaurant Happy Bowl Thai:
Investigators said they had not established a motive for the shooting rampage, which unfolded less than three miles from the White House. As for whether it may have been a terrorist attack, Mayor Vincent Gray said: 'We don't have any reason to think that at this stage.'
The FBI took charge of the investigation.
President Barack Obama mourned yet another mass shooting in the U.S. that he said took the lives of American patriots. Obama promised to make sure 'whoever carried out this cowardly act is held responsible.'
The area that was targeted, known as Building 197, was part of the headquarters for Naval Sea Systems Command, which buys, builds and maintains ships, submarines and combat systems. About 3,000 people work at the headquarters, many of them civilians.
Witnesses described a gunman opening fire from a fourth-floor overlook, aiming down on people in the first-floor cafeteria. Others said a gunman fired at them in a third-floor hallway. It was not clear whether the witnesses on different floors were describing the same gunman.
Around midday, police said they were searching for two men who may have taken part in the attack one carrying a handgun and wearing a tan Navy-style uniform and a beret, the other armed with a long gun and wearing an olive-green uniform. Chief Lanier said it was unclear if the men were members of the military.
But later in the day, police said in a tweet that the man in the tan uniform had been identified and was not involved in the shooting.
As emergency vehicles and law enforcement officers flooded streets around the complex, a helicopter hovered overhead, nearby schools were locked down and airplanes at nearby Reagan National Airport were grounded so they would not interfere with law-enforcement choppers.
A short distance away, security was beefed up at the Capitol and other federal buildings, but officials said there was no known threat.
Todd Brundidge, an executive assistant with Navy Sea Systems Command, said he and other co-workers encountered a gunman in a long hallway on the third floor. The gunman was wearing all blue, he said.
'He just turned and started firing,' Brundidge said.
Terrie Durham, an executive assistant with the same agency, said she also saw the gunman firing toward her and Brundidge.
'He aimed high and missed,' she said. 'He said nothing. As soon as I realized he was shooting, we just said, 'Get out of the building.''
Rick Mason, a civilian program-management analyst for the Navy who works on the fourth floor of the building, said a gunman was firing from the overlook in the hallway outside his office.
Shortly after the gunfire, Mason said, someone on an overhead speaker told workers to seek shelter and later to head for the gates at the complex.
Patricia Ward, a logistics-management specialist, said she was in the cafeteria getting breakfast.
'It was three gunshots straight in a row pop, pop, pop. Three seconds later, it was pop, pop, pop, pop, pop, so it was like about a total of seven gunshots, and we just started running,' Ward said.
Ward said security officers started directing people out of the building with guns drawn.
One person died at George Washington University Hospital of a single gunshot wound to the left temple, said Dr. Babak Sarani, director of trauma and acute care surgery. A police officer and two civilian women were in critical condition at Washington Hospital Center, said Janis Orlowski, the hospital's chief operating officer.
Orlowski said the police officer was in the operating room with gunshot wounds to the legs. The police chief said the officer was wounded when he engaged the shooter who later died.
One woman at the hospital had a gunshot wound to the shoulder. The other had gunshot wounds to the head and hand.
Adm. Jonathan Greenert, chief of naval operations, was at the base at the time the shooting began but was moved unharmed to a nearby military installation
Anxious relatives and friends of those who work at the complex waited to hear from loved ones.
Tech Sgt. David Reyes, who works at Andrews Air Force Base, said he was waiting to pick up his wife, Dina, who was under lockdown in a building next to where the shooting happened. She sent him a text message about being on lockdown.
'They are under lockdown because they just don't know,' Reyes said. 'They have to check every building in there, and they have to check every room and just, of course, a lot of rooms and a lot of buildings.'
Naval Sea Systems Command is the largest of the Navy's five system commands and accounts for a quarter of the Navy's entire budget. Only security personnel were allowed to be armed on the grounds.
Mason, the program management analyst for the Navy, said there are multiple levels of security to reach his office. Everyone must show a building ID to get through a main gate, and at the building entrance, everyone must swipe a badge to pass through either a door or gate, depending on the entrance.
That 'makes me think it might have been someone who works here,' he said.
The Navy Yard has three gates, according to its website. One is open around the clock and must be used by visitors. A second gate is only for military and civilian Defense Department employees. The third gate is for bus traffic.
The Navy Yard is part of a fast-growing neighborhood on the banks of the Anacostia River in southeast Washington, blocks from the Nationals Park baseball stadium.
Associated Press writers Jesse Holland, Stacy A. Anderson, Brian Witte and Ben Nuckols in Washington contributed to this report.