A masked man stands next to a kneeling man identified as British citizen Alan Henning (L), in this still image taken from video released by Islamic State militants fighting in Iraq and Syria, on ．．． 較多 

A masked man stands next to a kneeling man identified as British citizen Alan Henning (L), in this still image taken from video released by Islamic State militants fighting in Iraq and Syria, on October 3, 2014. The video purported to show the Henning's beheading. The beheading of Henning was the fourth such killing of a Westerner by Islamic State, which has seized large swaths of Iraq and Syria and has been blamed for a wave of sectarian violence. Henning, a 47-year-old taxi driver from Salford in northern England, was part of an aid convoy taking medical supplies to a hospital in northwest Syria in December last year when it was stopped by gunmen and he was abducted. REUTERS/Social Media Website via Reuters TV (UNKNOWN - Tags: CIVIL UNREST CRIME LAW CONFLICT POLITICS) ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE. NO SALES. NO ARCHIVES. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS PICTURE IS DISTRIBUTED EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS 較少