A Virginia shooting range owner has said Navy Yard shooter Aaron Alexis had practiced for two consecutive days and bought ammunition from their store before going on the rampage killing 12 people on Monday.
An attorney for Sharpshooters Small Arms Range in Lorton, Virginia, J Michael Slocum, said Alexis had visited the store on Saturday and used a rented rifle and ammunition to practice at the range, ABC News reports.
Later, Alexis purchased a Remington 870 shotgun and about two boxes, containing 24 shells, of ammunition from the store, the report added.
The store vendor said his personal information was approved by the federal law to purchase the ammunition.
FBI officials have also confirmed that Alexis entered Building 197 of the Naval Sea Systems Command Headquarters with a shotgun and snatched another handgun from a guard after he shot him dead.
Alexis' hotel room is being hunt down to find a reason for his massacre.
Alexis was working as an IT subcontractor with Hewlett Packard and required a secret federal security clearance when he was re-hired in July.
Alexis also had a legitimate access to the Navy Yard and he used a valid pass to gain entry to the building, the officials said.