9/11 Investigation | Federal Bureau of Investigation They were the most lethal terrorist attacks in history, taking the lives of 3,000 Americans and international citizens and ultimately leading to far-reaching changes in anti-terror approaches and oper...

Our investigation of the attacks of #9/11 code-named #PENTTBOM,” short for PA, #Pentagon, and #TwinTowers Bombing—was our largest case ever. At its peak, more than half our agents worked to identify the #hijackers and their sponsors and, with other agencies, to head off any possible future..