14:24 26 September 2013
On September 16, Aaron Alexis, a former navy reservist and computer technician for a government contractor, launched an attack and killed 12 people.
Now, the FBI has revealed that Mr Alexis left a note explaining the reason why he committed such act – extremely low frequency radio waves.
He wrote: "Ultra-low frequency attack is what I've been subject to for the last three months, and to be perfectly honest that is what has driven me to this.”
FBI added that Alexis did not target a particular individual during the shooting. There is also no evidence suggesting that the attack was because of dispute in the work place.
Valerie Parlave, assistant director of the FBI's Washington field office, said: "There are indicators that Alexis was prepared to die during the attack and that he accepted death as the inevitable consequence of his actions.”
Meanwhile, deputy defense secretary Ash Carter said that the department would review the security clearance process. He added: "Bottom line is, we need to know how an employee was able to bring a weapon and ammunition onto a DoD installation, and how warning flags were either missed, ignored or not addressed in a timely manner.”