11:46 a.m. ET -- It's back to baseball Tuesday for the Washington Nationals, who postponed a Monday game as the organization allowed the Navy to use one of its parking lots as a site where Navy Yard evacuees could reunite with their loved ones.
The Nationals will wear their "Patriotic Blue" jerseys in the first game of a double-header with the visiting Atlanta Braves, the team said. The first game, to start at 1:05 p.m., is the makeup for Monday's postponement.
The Navy Yard is just blocks from Nationals Park.
11:30 a.m. ET -- Navy Secretary Ray Mabus on Tuesday will "order reviews of all physical security at all Navy and Marine Corps installations," a U.S. Navy official told CNN's Barbara Starr.
"The first will be a quick look to ensure all physical security requirements are being met. The second will be a deeper review to ensure the right physical and personal security requirements are in place," the official said.
11:21 a.m. ET -- Arrests don't automatically prevent people from getting a security clearance, says Anita Gorecki-Robbins, a military justice lawyer.
Alexis, who had been arrested a few times since 2004, received a Department of Defense security clearance so that he could work for The Experts, a subcontractor of HP Enterprise Services that was contracted to "refresh equipment used on the Navy Marine Corps Intranet network," according to a statement released by his employer.
Gorecki-Robbins told CNN's Chris Cuomo and Ashleigh Banfield that the Defense Department can decide to give security clearances to people who have been arrested. In Alexis' case, either the arrests weren't picked up in screening or "someone did see (the arrests) and decided to give it to him anyway."
10:19 a.m. -- A former Army attorney says the shooting should raise questions about whether military installations should randomly check vehicles.
Alexis drove into the Navy Yard because he had a valid military-issued ID and was assigned to work there as a contractor. Greg Rinckey, a former attorney in the Army judge advocate general's office, told CNN's John Berman that the shooting could boost arguments for random vehicle checks, even for people with valid credentials.
10:09 a.m. ET -- To honor the shooting victims, Defense Secretary Chuck Hagel and Joint Chiefs of Staff Chairman Martin Dempsey have just placed a wreath near the "The Lone Sailor" statue at Washington's U.S. Navy Memorial plaza.
Other federal officials are marking the shooting, too. Nearly 10 minutes ago, the U.S. Senate observed some moments of silence.
9:59 a.m. ET -- If you're wondering how Alexis could have been honorably discharged from the Navy Reserve in 2011 after a pattern of misconduct, a former Army attorney might have an answer.
Greg Rinckey, a former attorney in the Army judge advocate general's office, told CNN's John Berman that a pattern of misconduct doesn't necessarily result in an other-than-honorable discharge -- but an honorable discharge might not be Alexis' full story, either.
"Most people with patterns of misconduct are discharged usually with an other-than-honorable discharge or a general discharge," Rinckey, of Albany, New York, said Tuesday morning. "I think we need to dig a little bit further into this to see if it was a general-under-honorable-conditions discharge or an honorable discharge."
Alexis, who served as a full-time Navy reservist from 2007 to January 2011, was honorably discharged after a "pattern of misconduct," a U.S. defense official with knowledge of the investigation told CNN earlier on condition of anonymity. The official did not detail the misconduct.
9:17 a.m. ET -- Of the eight injured survivors, the three who were shot were doing better today at MedStar Washington Hospital Center. A Washington policeman is in fair condition, a female civilian is in fair condition, and another female civilian is in good condition.
The police officer was shot in his legs. As of Monday night, medical personnel had yet to determine whether he would be able to keep the limbs, CNN's Chris Lawrence reported.
9:02 a.m. ET -- Alexis recently made contact with two Veterans Administration hospitals for apparent psychological issues, law enforcement sources said Tuesday.
8:57 a.m. ET -- Alexis was arrested in August 2008 on a charge of disorderly conduct in DeKalb County, Georgia, county police said Tuesday.
This is in addition to at least two other arrests, dating back to at least 2004 when he was arrested in Seattle. In that incident, he was accused of shooting out the tires of a man's truck in an anger-fueled "blackout," a Seattle Police Department report said.
In 2010, Alexis was arrested by Fort Worth, Texas, police but never charged over an allegation that he fired a gun through the ceiling of his apartment. According to records, he told police he accidentally fired it while cleaning it.
8:55 a.m. ET -- Authorities have recovered three weapons from the scene of the shooting, federal law enforcement sources said. Investigators say they think Alexis brought a shotgun into the compound and may have taken two handguns from guards, the sources said.
Initial reports said Alexis used an AR-15 semiautomatic rifle during the attack, but by Tuesday, law enforcement sources with knowledge of the investigation said that was not the case.
It is thought that Alexis had rented an AR-15, but returned it before Monday's shooting, the officials said.