British Prime Minister David Cameron vowed on Friday to use all means at his disposal to hunt down militants such as "Jihadi John" after the killer was identified as a Kuwaiti-born computer programming graduate from London. The black-clad militant brandishing a knife and speaking with an English accent was shown in videos released by Islamic State (IS) apparently decapitating hostages including Americans, Britons and Syrians. "When there are people anywhere in the world who commit appalling and heinous crimes against British citizens, we will do everything we can with the police, with the security services, with all that we have at our disposal to find these people and put them out of action," Cameron said. Cameron refused to comment on the identification of "Jihadi John" as 26-year-old British militant Mohammed Emwazi, but said that people should get behind the security services, which he praised as impressive and dedicated to defending Britain. Emwazi was known to the security services, which had tried to recruit him, according to prisoners' group Cage. The case has sparked debate about whether the security services let him slip through their grasp to join IS in Syria. Dressed entirely in black, a balaclava covering all but his eyes and the bridge of his nose and a holster under his left arm, Jihadi John became a menacing symbol of Islamic State brutality and one of the world's most wanted men. He used videos to threaten the West, admonish its Arab allies and taunt President Barack Obama and Cameron before petrified hostages cowering in orange jump suits. Emwazi's name was first disclosed by the Washington Post. Two U.S. government sources who spoke on condition of anonymity told Reuters that investigators believed Jihadi John was Emwazi. The Sun and The Daily Mail newspapers published a picture showing a schoolboy Emwazi smiling and sitting cross-legged on the grass at the front of the photograph from the St Mary Magdalene Church of England primary school in Maida Vale, West London. A picture of him as a student was later broadcast by Sky News, showing a young man with a moustache and goatee beard, wearing a cap with a logo resembling the P from the Pittsburgh Pirates U.S. Major League Baseball team.
