From where I recall being when I killed the guy (3rd floor of tower), you could see me from 3 places.
1) Above me, on the floor above; you said you were below me.
2) The ladder from the second floor, which was in front of me from my perspective, and if you can see that floor from the ladder, everyone on the floor can see you.
3) Outside, below and behind me, looking through the window. You said you wer in the tower.
From my perspective, being in the tower, being below and behind me, and seeing the kill aren't possible.