WASHINGTON, D.C. -- The Washington Navy Yard remains closed Tuesday, except for essential personnel. The closure comes as the FBI investigates Monday's shooting that killed more than a dozen people, including the alleged gunman.
The media is now learning more about Navy veteran Aaron Alexis and the grudge he may have had against the military.
Authorities believe 34-year-old Aaron Alexis was the lone shooter. They say as a military contractor, he had legitimate access to the Navy Yard. However, what they don't know is why the shooting happened.
As for the shooter's motive, Washington, D.C. Mayor Vincent Gray says it's unclear.
Meanwhile, the FBI says agents may be on site another two days, investigating.
"We continue to work to find where he has been, who he has talked to, and what he has done," said FBI investigator Valerie Parlave. Agents are reportedly getting warrants to search Alexis' car and hotel room.
Others are backtracking Alexis' roots in Virginia, and where he's believed to have bought a shotgun at a Texas store.
In Washington State and in New York, Alexis' relatives are stunned. Anthony Little is Alexis' brother-in-law.
"No one saw it coming," Little said. "No one knew anything. So all of this, it's just ... shocking."
Officials say those wounded in the Washington, D.C. attack will recover. Yet, the emotional wounds experienced by more than 20,000 area workers affected by the incident may take longer to heal.
In the meantime, lawmakers are considering an independent investigation into the shooting, and congress may look at beefing up security in the area.
As for the mood in Washington, D.C., traffic has resumed, schools in the area have reopened, and flags will fly at half staff though Friday.