Easy "Sandman" and "Waste Not" trophies
Get the Deadeye and look out the window to find a building with five Grims standing.They are located as follows: one on the fire escape on the right, two on the roof directly in front, and two on the higher roof behind the building. Use the Deadeye to headshot the Grims to uearn the "Sandman" trophy. By not reloading you will also earn the "Waste Not" trophy.