Investigators rule out possibility of second gunman

UPDATE: Authorities announced at a late-evening press conference that they are no longer seeking a second suspect in this morning’s shooting at the Washington Navy Yard.

Law enforcement officials also revealed that the suspect, Aaron Alexis, had a valid security ID to enter the building where the shooting took place.

So far, seven of the 12 shooting victims, who range in age from 46 to 73 years old, have been identified and their families notified. Officials noted that no active duty military personnel were among the victims.

Eight other people were injured during the shooting. Three were shot but are not in any danger.

UPDATE (5:02 p.m.): The Navy says 34-year-old Aaron Alexis, the suspected gunman in this morning’s Washington Navy Yard shooting, was a full-time reservist from 2007 to 2011.

The Navy said in a release Alexis, who died at the scene in a shootout with police, left the Navy on Jan. 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, Texas. The Navy says his home of record was New York City.

UPDATE (4:23 p.m.): A 13th person has died from this morning’s shooting at Washington Navy Yard. The 13 deaths include the suspected shooter, identified as Aaron Alexis of Fort Worth, Texas, who died in a gun battle with police at the scene.

UPDATE (3:33 p.m.): Law enforcement officials have identified the suspected Washington Navy Yard gunman as Aaron Alexis, 34, of Texas, who was killed at the scene of the shooting. Police continue to search for a second suspect. One other person who was being sought reportedly was later found and cleared of any wrongdoing.

The FBI has taken charge of the investigation.

Investigators said they had not established a motive for the shooting. 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 Washington Nationals, whose stadium is near the site of the shooting, have postponed Monday night’s baseball game against the Atlanta Braves.

UPDATE (2:09 p.m.): Officials now say that 12 people, including the suspected shooter, have died in this morning’s Washington Navy Yard shooting.

OUR EARLIER REPORT (1:30 p.m.): Police say gunmen wearing military-style uniforms may have opened fire at 8:20 a.m. EDT this morning inside a building at the Washington Navy Yard, killing at least six and wounding four others, including a law enforcement officer.

Washington, D.C., Police Chief Cathy Lanier announced at a midday press conference that one of the suspects in the shooting is dead, while at least two others possibly remain at large.

“The big concern for us right now is that we have potentially two other shooters that we have not located at this point,” Lanier said.

Patricia Ward, a logistics management specialist who works at the Navy Yard, which houses Naval Sea Systems Command (NAVSEA) headquarters, was in the cafeteria when she heard shots. “Everybody just panicked at first,” she said. “It was just people running, running, running.”

Ward explained to the Los Angeles Times that, in order to enter the building, a person must scan an ID card and put his or her bags through a metal detector. But she added that there is no metal detector for the body. She said this is how the shooters may have got weapons inside.

Witnesses said a gunman opened fire from the fourth floor, aiming down on people in the first-floor cafeteria. Others, including Todd Brundidge, an executive assistant with NAVSEA, encountered a gunman in the hallway of the third floor.

The gunman was wearing all blue, Brundidge recalled.

“He just turned and started firing,” Brundidge told WJLA. “Everyone was going down the stairs. They were pushing. They were shoving. People were falling down … climbing the wall trying to get over the wall to get out of the spaces. It was just crazy.”

NAVSEA is the largest of the Navy’s five system commands and accounts for a quarter of the Navy’s entire budget. About 3,000 people work at the Navy Yard facilities, helping build, buy, and maintain the Navy’s ships, submarines, and combat systems.

Meanwhile, administrators have put nearby schools on lockdown and grounded airplanes at Reagan National Airport. Security officials increased security at the U.S. Capitol and are giving President Barack Obama frequent briefings on the shooting.

Obama said he mourned what he called “yet another mass shooting” in the United States taking the lives of American patriots. Obama promised to make sure “whoever carried out this cowardly act is held responsible.”

The Associated Press contributed to this report.