ansar al sharia, the group the u.s. blames for the 2012 attack on the u.s. compound in benghazi. intelligence gleaned from local libyans helped draw khattalah to the location. u.s. commandos captured him with no shots fired, no one getting hurt. a surprising feat, one former libyan intelligence official tells cnn, because khattalah usually surrounded himself with guards. u.s. commandos whisked him to a navy ship in the mediterranean to begin undergoing questioning for his role in the attack and anything else he knows about terrorist activity. officially, the pentagon will say little. >> i'm not going to get into specifics on the actual execution of the operation. >> reporter: president obama touted the capture. >> it's important for us to send a message to the world that when americans are attacked, no matter how long it takes, we will find those responsible and we will bring them to justice. >> reporter: but some wonder why