WASHINGTON (CBS/AP) – Federal law enforcement officials say the man accused in a shooting rampage at the Washington Navy Yard that left at least 13 people dead has been identified as Aaron Alexis.

The two officials spoke Monday to The Associated Press on condition of anonymity because they were not authorized to speak publicly.

Officials Alexis was a 34-year-old from New York City, but most recently lived in Ft. Worth, Texas. He is counted among those dead.

Records show Alexis was arrested twice — once in 2010 on suspicion of discharging a firearm within city limits and another time in 2004 for allegedly shooting out the tires of another man’s vehicle.

That official says Alexis is believed to have gotten into the Navy Yard by using someone else’s identification card. The person whom the ID card belonged to had been placed on administrative leave last fall.

(Photo by FBI via Getty Images)

Aaron Alexis (Photo by FBI via Getty Images)

Alexis was a Navy reservist from 2007 to 2011 and was discharged as a petty officer 3rd class. After that, he worked as a waiter and delivery driver at Happy Bowl Thai restaurant in White Settlement, a suburb of Fort Worth, until May 2013.

“He was a very nice person,” said Afton Bradley, a former co-worker at the Thai restaurant. “It kind of blows my mind away.”

Mayor Vincent Gray says the 12 shooting victims range in age from 46 to 73 years old.

Police were searching for a second possible suspect in the attack at the Washington Navy Yard.

However, late Monday night, officials said they believe Alexis was the lone gunman.

Witnesses described a gunman opening fire from the fourth floor, aiming down on people in the first-floor cafeteria. Others said a gunman fired at them in a third-floor hallway.

As witnesses emerged from the building, a helicopter hovered over the building, schools were on lockdown and airplanes at nearby Reagan National Airport were briefly grounded.

Former SWAT Team leader talks about Navy Yard shooting from a tactical standpoint on NewsRadio 1020 KDKA:

According to WJZ-TV in Baltimore, the conditions of those injured are unknown at this time, but there are reports that at least two of the people hurt are police officers.

At least one gunman opened fire inside the Naval Sea Systems Command headquarters, where about 3,000 people work just miles from the Capitol.

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