The Islamic State group on Saturday released a video showing the execution of British aid worker David Haines in the same grisly manner as the murder of two American journalists in recent weeks, The Washington Post reported.
The video, titled “A Message to Allies of America,” appears to show Haines clad in an orange jump-suit kneeling beside a man who speaks in the same London-accented English as the apparent executioner in two previous videos.
The masked man addresses British Prime Minister David Cameron, telling him that the killing is retribution for “your evil alliance with America, which continues to strike the Muslims of Iraq.”
The video ends with a threat to kill a man, Alan Henning, whom Islamic State claimed is another British hostage of the terrorist group, according to The Washington Post.
Cameron tweeted a statement late Saturday saying that “the murder of David Haines is an act of pure evil. My heart goes out to his family who have shown extraordinary courage and fortitude.”
Cameron also vowed to “do everything in our power to hunt down these murderers and ensure they face justice, however long it takes.”
A British Foreign Office spokeswoman had earlier said the government was “working urgently to verify” the video’s content.
“If true, this is another disgusting murder,” said the spokeswoman, who spoke on the customary condition of anonymity. “We are offering the family every support possible. They ask to be left alone at this time.”
The apparent killing of Haines, a 44-year-old father of two from Scotland who was working for the French aid agency ACTED, is likely to intensify calls in Britain for more direct action against Islamic State.
Britain has previously said it is sending arms to Kurdish fighters who are battling the group, and is supporting American airstrikes with surveillance and intelligence.
Britain has so far refrained from carrying out airstrikes itself. But Cameron and his allies have suggested that they may be open to direct British military intervention.
Islamic State has released two previous videos showing the execution of the American journalists James Foley and Steven Sotloff. The group threatened to kill Haines at the end of the Sotloff video.
Meanwhile, U.S. President Barack Obama released a statement late Saturday condemning Haines’s killing.
“Our hearts go out to the family of Mr. Haines and to the people of the United Kingdom. The United States stands shoulder to shoulder tonight with our close friend and ally in grief and resolve,” he said.