Alexis, who reportedly had a "pattern of misconduct" in the Navy, was suffering from PTSD.
It’s all information coming out about Aaron Alexis, the man police say is responsible for yesterday's shooting at the Navy yard.
But as we are discovering, none of that stopped Alexis from keeping his secret security clearances to get access to the base.
He served his country as a petty officer 3rd class in the Navy Reserve, working as an aviation electrician at an air station in Fort Worth Texas.
But now, Alexis is accused of murdering 12 civilians after walking onto the Washington Navy yard with a valid military ID.
After he separated from the Navy in 2011, Alexis started working for military contractors.
His latest position was an IT professional with Hewlett Packard subcontractor "The Experts."
The company tells NewsChannel 3 that Alexis passed their background checks twice in the past year, as well as a secret security clearance confirmation by the Department of Defense.
The last one took place this past July, and the only thing they found was a minor traffic violation.
There was no mention of his two arrests in 2004 or 2010, one for shooting out the tires of someone's truck, the other for discharging a firearm into the ceiling of his apartment.
So how can a person with two gun arrests pass a background check and get a security clearance?
Both of his cases were never officially prosecuted and he was never convicted.
According to DOD guidelines on security clearances, the only basis for automatic denials would be a criminal conviction where you serve a year or longer in jail, a determination of mental incompetence by a DOD approved mental health professional, or a dishonorable discharge.
Even though Alexis told police in the past he suffered from PTSD, he was never declared mentally incompetent.
And according to CBS News, Alexis was honorably discharged by the Navy despite a "pattern of misconduct."
That honorable discharge helped him pass all background checks to get a valid military ID accessing the Washington Navy Yard.
Now how he got into the Naval Sea Systems Command still has yet to be determined.
The FBI said this afternoon he got into the secure building with a valid ID, but didn't say that if that ID belonged to Alexis, or someone else.