An Internet video shows an ISIS militant beheading British aid worker Alan Henning, NBC News reported. Henning, who was captured by ISIS in December and threatened in a video released last month, is the fourth Westerner to be beheaded by the Islamist militant group. “The brutal murder of Alan Henning by ISIL shows just how barbaric and repulsive these terrorists are,” said U.K. Prime Minister David Cameron, who vowed to hunt down those responsible. At the end of the new video, American citizen Peter Kassig is shown and threatened with execution next.
