ISIS released a video Friday afternoon showing the brutal execution of British aid worker Alan Henning. The beheading video is the fourth released by the Islamic militant group, following ones showing the executions of two Americans and one British citizen.

The clip, like the three other execution videos, begins with the captive speaking to the camera while his masked executioner holds a knife.

"Hi, I'm Alan Henning. Because of our parliament's decision to attack the Islamic State, I as a member of the British public will now pay the price for that decision."

A quick edit follows and the executioner, apparently the same one as in the other videos, speaks. "The blood of David Haines was on your hand, Cameron. Alan Henning will also be slaughtered, but his blood is on the hands of British parliament."

The executioner then begins to saw at Henning's neck as the video fades to black. The next image shows Henning's dead body, with his severed head resting on his torso.

"Obama, you have started your Arab bombardment... It's only right that we continue to strike the next of your people," the executioner says at the video's end as a man, identified in the video as Peter Edward Kassig, an American, sits on his knees.

Henning, a Taxi driver from Manchester, was abducted on December 26, 2013 as he worked with several friends to distribute medical equipment to refugees in Syria. In late September, his wife, Barbara Henning, released a statement pleading for her husband's life.

"We are at a loss why those leading Islamic State cannot open their hearts and minds to the truth about Alan's humanitarian motives for going to Syria and why they continue to ignore the verdict of their own justice system," she said, according to the Guardian. "Surely those who wish to be seen as a state will act in a statesmanlike way by showing mercy and providing clemency."

UPDATE 4:44 pm: Shortly after the release of Henning's execution video, ISIS reportedly published a second video.