Handgun Rounds (2×30) - On the floor amongst the boxes on the landing area at the top of the stairs. One is directly opposite the stairs, the other is in the corner on the other side.
Handgun Rounds (1×15) - On the barrel just opposite the elevator.
Handgun Rounds (1×15) - Only acquirable when playing as either Cindy or Kevin. On the ground next to the wounded police officer in the west corner of the roof.