WTF he's death!! Sewers SPOILER!

[Kman]

yeah i think you're supposed to assume that it was a brute that killed it since when you exit the room a brute comes through the gate and you have to hide in that same room you just came from. then again the room is coated in the shadows organic tissue and also the brute would have had to find some other way in since the when you enter the sewer the wheel you have to stop is running and the only other entrance to that room is the gate which is still intact when you find the dead grunt.