British aid worker David Cawthorne Haines has become the latest victim of the Islamic State militants, who released a video of his beheading on Saturday.
Multiple reports have analysed and confirmed that the visuals of Haines' beheading are consistent with that of the executions of two American journalists James Foley and Steven Sotloff.
Haines, a 44-year-old father of two from Perth in Scotland, was kidnapped in Syria last year, while working for the French agency ACTED.
The video titled, "A Message to the Allies of America", is addressed to UK Prime Minister David Cameron. It talks about Britain working with the US, the Iraqi government and Kurdish Peshmerga forces to defeat Islamic State.
"This British man has to pay the price for your promise, Cameron, to arm the Peshmerga against the Islamic State," said a masked man dressed in black, with a British accent, standing over Haines who is seen wearing an orange jumpsuit.
The video then shows the beheading of Haines, who is seen kneeling on the ground.
At the end of the clip, Alan Henning, also a British citizen, is shown. And the masked man warns that Henning will also be killed, if Cameron continues to support the fight against Islamic State.
Haines also spoke, saying Cameron was responsible for his execution.
"You entered voluntarily into a coalition with the United States against the Islamic State, just as your predecessor, Tony Blair, did," Haines said.
"Following a trend amongst our British Prime Ministers who can't find the courage to say no to the Americans. Unfortunately, it is we, the British public, that will in the end pay the price for our Parliament's selfish decisions."
Foley and Sotloff made similar speeches, addressing US President Barack Obama, which have been dismissed as scripted by Islamic State and delivered under duress.
Cameron condemned the killing and stressed he would bring the killers to justice.
"This is a despicable and appalling murder of an innocent aid worker. It is an act of pure evil. My heart goes out to the family of David Haines who have shown extraordinary courage and fortitude throughout this ordeal," Cameron said in a statement, quoted by Reuters.
"We will do everything in our power to hunt down these murderers and ensure they face justice, however long it takes."
The executioner appeared to be the same British-accented man, who appeared in the beheading videos of Foley and Sotloff, in a similar desert setting. In all videos, the captives were seen wearing orange jumpsuits.
Graphic video, discretion advised
Meanwhile, President Obama, in a statement released on Saturday, said that the United States strongly condemns "the barbaric murder" of Haines.
"We will work with the United Kingdom and a broad coalition of nations from the region and around the world to bring the perpetrators of this outrageous act to justice," Obama said, as reported by The New York Times.
Obama is now calling for a coalition of Western and Middle Eastern countries to fight Islamic State and has suggested that the US intends to bomb Islamic State positions in Syria.