Aaron Alexis, Texas Man, Identified as Suspect in Washington Navy Yard Shooting: Reports

September 16, 2013 Updated: September 16, 2013

Aaron Alexis, a 34-year-old Texas man, was identified as the alleged gunman in the mass shooting in Washington D.C., and he used a former employee’s identification card to get into the Washington Navy Yard, it was reported

 The Associated Press, citing law enforcement sources, confirmed Alexis was the alleged gunman.

 He recently began working as a civilian contractor for the Navy. Law enforcement officials told NBC News that they identified him via fingerprints.

 It is unclear what his motive was, reported USA Today.

“What we lack is a sighting of somebody shooting, other than the dead shooter,” said a law enforcement official, who was not named, according to USA Today, which also confirmed the shooter was Alexis.

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.”

At least 12 people were killed, D.C. Mayor Vincent Gray said in a press conference.

In addition to the dead, at least three people were wounded.

The area where the rampage took place, known as Building 197, was part of the headquarters for Naval Sea Systems Command, which buys, builds and maintains ships, submarines and combat systems. The yard is a labyrinth of buildings protected by armed guards at gates and metal detectors, and employees have to show their IDs to come and go.

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 cafeteria on the main floor. 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.

The Associated Press contributed to this report.