After the fall of the Taliban five years ago, some experts warned of a nightmare scenario in which the Taliban and Al Qaeda would escape from Afghanistan into neighboring Pakistan and set up new command centers far out of America's reach.

That nightmare scenario has now come true. The Taliban controls large parts of the lawless tribal areas along the border. In a video obtained by FRONTLINE, the Taliban demonstrate their brutal brand of justice. After executing 17 people, said to be thieves, in front of a crowd of hundreds, they hung the bodies on poles for three days. "We have killed these people and sent them to God," a Taliban gunman says to the camera. "God will bring them to justice."