The ISIS (Islamic state of Iraq and the Levant) keeps recruiting different citizens of different country to join in it's cause of it's own Islamic caliphate. We have seen citizens of Australia that have travelled to join the Islamic state and seen a man and his young boy with a severed head in the past month.
In the newly released video of ISIS, showing the beheading of the American Journalist James Foley. The ISIS member that beheaded the American citizen was called, John the Jihadist, a man that is said to have come from London and now supporting the ISIS group.
Also in a video that shows Syrian that were captured in the Syrian army base digging a hole that is said to be their death grave shows a man that analyst supposedly said is from North American sending his message to American and he seems to be the new executioner supposedly used to be John the Jihadist role in the group.