Is there evidence whatsoever they were in any way "butchered?"
I am not a hunter but was taught how to use a combat knife in the military. People think using knives lethally is either some choreographed nonsense out of west side story, or some charnal house thing with entrails and bodies cut into pieces.
In reality you are taught to use the knife with stealth and make one or two deep powerful wounds in thorax. That is going to, to a virtual certainty, silence and lethality wound anyone. If they are sleeping somewhat intoxicated and barely waking, the victim could try and block the strike, or grab the knife blade and get defensive wounds. It isn't butching, has nothing to do with hunting, and can be quite silent