Investigators say Aaron Alexis lied about a previous arrest and failed to disclose thousands of dollars in debt when he applied for a security clearance.
According to Tarrant County, Texas officials, Alexis was arrested on Sept. 4, 2010 on accusations he recklessly discharged a firearm inside the limitations of municipality.
During the later investigation, officials learned that the deceased gunman was cleaning a gun in his apartment when it went off and a bullet entered an upstairs apartment. No one was injured and the case was dropped.
Seattle police say they also arrested Alexis in 2004 for shooting out the tires of a car. Detectives say the car belonged to construction workers who had parked it near a home where Alexis was staying.
When police later arrested Alexis, he claimed the construction workers had disrespected him. Alexis said it triggered an anger-fueled blackout and that he didn't even remember firing his weapon until an hour later.
Federal investigators dismissed the omissions and made one of their own by deleting any reference to Alexis' use of a gun in those arrests.
Instead, the report from the Office of Personnel Management said Alexis "deflated" the tires of a car in the 2004 incident. His reaction was described as retalitation for the construction worker putting an unknown substance in Alexis' gas tank. It was not clear Monday who was at fault for the ommission.
The gaps in his record allowed him to have access to a secure Navy facility despite a string of behavioral problems and brushes with the law.
The Navy also released other details about Alexis' troubled service record including a disorderly conduct arrested outside a nightclub in Georgia in September 2008.
Defense Secretary Chuck Hagel has since ordered two sweeping reviews of military security and employee screening programs.
In the meantime, one of the two remaining patients injured in the incident has been discharged from the hospital.
Alexis, 34, was killed following a gun battle with D.C. and U.S. Park police.
The Associated Press contributed to this report.