The Navy was unaware until after the killings at the Washington Navy Yard that gunman Aaron Alexis had been arrested in 2004 for shooting out the tires on a vehicle and claiming he had blacked out in anger , a senior Navy official told reporters Monday . However , the government agency that carried out Alexis ' background check in 2007 did know that he omitted information about that brush with the law but granted him security clearance anyway after Alexis explained it . The Navy said it did n't learn the details of the incident until after Alexis killed 12 people last week at the sizable naval installation in Washington . In 2007 , contractor USIS conducted the security clearance assessment for Alexis , who had just joined the Navy . Flags in shooter 's past apparently not red enough . A report for the Navy from the Office of Personnel Management , which processes and grants security clearances , did n't mention a gun , the Navy official said . It said only that Alexis had `` deflated the tires on a construction worker 's vehicle '' in the 2004 incident , which occurred in Seattle . According to the Office of Personnel Management , the agency uncovered Alexis ' arrest for malicious mischief through a check of FBI criminal history records . The Seattle Police Department would not make records available , and the agency tried to corroborate the arrest through court records . The Navy said Alexis answered `` No '' to questions on his security clearance form about whether he had ever been arrested or charged with a felony . Alexis told the security clearance personnel he did not disclose the malicious mischief charge because he was told it was going to be dismissed and removed from his record . The search of the court records corroborated Alexis ' version , the Office of Personnel Management said , but these records did not mention that a weapon was used . During a follow-up interview , Alexis did not mention having shot the tires out . `` Had the Seattle Police Department permitted OPM to obtain the law enforcement records , it is possible that additional information may have been obtained , '' the agency said in a statement . Alexis , 34 , was a subcontractor last week when he entered the Navy Yard and the shooting rampage began . In addition to the 12 deaths , Alexis wounded eight people before he was killed . A woman who was wounded in the shooting was released from a hospital Monday . Only one person remains hospitalized -- a police officer who is listed in good condition . USIS is the same contractor that processed NSA leaker Edward Snowden 's clearance and is now under investigation . Obama at Navy Yard memorial : 'We ca n't accept this '
One of the wounded victims was released from a hospital bed . Navy was not told in 2007 that Aaron Alexis had shot out tires of a car , senior official said . He says the Navy spokesman has denied ever having been charged with a felony . Alexis left 12 people dead before he was killed .