• Slickly edited footage shows boy, about 14, loading handgun in warehouse
  • Prisoner driven to execution by a group of masked militants in saloon cars
  • Boy forces victim to kneel then vows to avenge U.S., Russia and Europe
  • The teeanger appears to shoot prisoner three or four times in the head

A chilling video that appears to show a boy executing an alleged Iraqi spy has been released by the Islamic State.

Slickly edited footage shows the teenager, of Western appearance, loading a 9mm handgun as the prisoner is driven into a warehouse by a group of masked militants.

The boy, believed to be around 14 years old, forces him to kneel on the ground and removes his blindfold before making a statement in Arabic vowing to avenge the U.S., Russia and Europe.

He then crouches next to the victim…