My friends were mighty pleased with what you did on Shoreline. And they definitely want some more. More profit in it for you, too. Some extra gear too, so go on, keep doing good things for good people. Ah, almost forgot. They are asking for half-masks, you know, those that Scavs hide their faces with. Grab them from the bodies, they won't need them anymore, but my friends do. No idea what they need them for, probably to make a point or something. One more thing, this time it should be done silently, with a suppressor, so that they don't even know what killed them. To work, soldier.
Enter the map Shoreline and search for and kill 12 Scavs whom can be found throughout the map.
Scavs can typically be found in the red marked areas during a raid:
Care should be taken when engaging Scavs at the extraction points as players may accidentally stumble on you and surprise you. This is especially true for the rock passage area since players in the resort will hear gunshots clearly and know exactly where you are.