I'm at the part where you have to go in diguise again, i can get the first set of papers, however to get the second set i have to kill that officer that ask for my papers correct? i tried that and then all the enemies started shooting at me even though i had my gun away, what do i do?

Kill the officer when nobodie can see you

Use your walk key, go in the room with the boxes, WALK up behind to the table, grab papers WALK back out, stay away from the officer. WALK WALK WALK WALK WALK WALK not run.