but the murder of 44-year-old david haines on tape was no less horrifying. >> david has been murdered in the most callous and brutal way imaginable by an organization which is the embodiment of evil. >> reporter: as intelligence agencies looked for clues in the video, it appeared to be the same purported executioner with a british accent seen on the videos of americans james foley and steven sotloff. >> this british man has to pay the price. >> people across this country would have been sickened by the fact that it could have been a british citizen. a british citizen who could have carried out this unspeakable act. >> reporter: the setting in the new video is approximately the same. but without the distinguishing road, rock and plant landmarks seen before. isis is aware that u.s. drones have been flying over the area trying to track the location of the hostages or even the execution site. haines, the father of two