TODAY | September 26, 2013
>>> showing the gunman inside the facility. justice correspondent pete williams has the latest on. matt, good morning, ten days after the shooting spree, employees who work in the building where it happened are still not allowed back in. evidence seems to continue working, but we have a clearer picture of what happened and why. the fbi says family members of the victims were notified before the materials you are about to see were released. the fbi released under surveillance video of aaron alexis ultimately hiding in the building.
>> there is evidence he prepared to die as the inevitable consequence of hissing as.
>> reporter: he emerges from a restroom on the 4th floor, holding the shotgun low, looking into office doors. another view shows him coming down a stairway. investigators say he shot on three floors. a final video shows him hiding behind the corner at the other end of the hallway. when the fbi discovered his shot guns, they discovered he had shot it down, scratching into the barrel and the torment. on the bid of the gun, not what you all say, better off this way and my elf weapon t. search of a backpack, he recently wrote, ultralow frequency attack is what i have been subject to the last three months and to be perfectly honest, that is what has driven me to this.
>> alexis held a delusional belief he was being controlled and influenced by extremely low frequency or elf, electronic weapons.
>> reporter: conspiracy theorists believed it could be used for mind control t. fbi says there was no evidence alexis was targeting anyone in particular or any work place dispute set him off.
>> all right. pete williams , thanks,