How do I beat the copycat killers?

Ok first switch to tech vision, (the green one scroll with the dpad), and you will be able to see the killers in their cloaked forms in a much clearer fashion. Then all you must do is look around the city for them, particularly in areas of gang violence. Once found, switch to open hand, no blades, and beat them until he picks them up, then you should see three waypoints, simply take three of them, one to each waypoint marker, and he will flay them.