reporter: he sis the killer menacingly brandishing a knife in the executions of hasostages james foley, peter kasic and many more. my knife will execute the next of your people. reporter:r and now he is identified as mohammed emwazi a british national born in kuwait but raised in london. he is a top terror target. in the mind of the president, he se ranking high on the list, because that individual is responsible for the killings of innocent american ss. reporter: he is dubbed a number of the killers after the beatles. john stood for john lennon and then the british tabloids added jihadi. he is from a well off pamly, and