trajectory that's unfamiliar for us. >> reporter: emwazi's friends say his path to radicalization may have begun in 2009 when he traveled to tanzania to go on a safari a graduation present from his parents. but he was detained on arrival, held overnight, then deported to the uk. authorities suspecting his true intention was to travel to somalia. in 2010 he was detained again by counter terrorism officials in britain. two years later, emwazi is believed to have traveled to syria, where he joined isis. his friends claim mistreatment by british authorities set him on a path to terrorism. >> our entire national security strategy for the last 13 years has only increased alienation has only increased people feeling like they don't belong. >> that was a fairly alarming defense, considering emwazi's truly brutal crimes particularly for families of his victims. today the daughter of one of his victims, the british aide