It appears Alexis had been arrested several years ago for discharging a firearm within city limits, according to Mediaite.
Alexis is a native of Fort Worth, Texas who recently worked as a civilian contractor in Washington, D.C.
An arrest record from Tarrant County in September of 2010 shows he was arrested for discharging his weapon.
At the time, a neighbor phoned police after hearing a bullet pass through her floor and ceiling.
He told authorities he had been cleaning the weapon when it slipped and he accidentally pulled the trigger.
The police report was filed with the District Attorney’s office, but charges were never filed.
Alexis had been suffering from several serious mental problems of late, including paranoia and a sleep disorder, and had been hearing voices in his head, according to ABC2News.
He had been treated since August by Veterans Affairs, the officials said.
At least 12 people were killed in Monday’s shooting spree. The U.S. Senate complex is currently on lockdown and tonight’s Nationals v. Braves baseball game has been cancelled.