The smell of blood is very distinct. Especially a lot of it. But in hunting, they had to be used to that odor. They probably wore some sort of balaclava hood that covered their nose (and most of the facial area) which may have helped w/keeping out the blood smell, during the massacre.
This was a mission, to wipe out CR1s branch of the R family tree. KR & GR, were part of their plan to throw off LE, I believe.
I can't get over a clan this tight. Taking it from anger, to hate, to fantasy, to first voicing the idea, to obtaining the items & making a plan, and all the way up to murdering, eight people, up close and personal, who you know, one who practically lived with your family, and is the mother of your child, another only 16, and two, sleeping with their six month old, and a toddler in the next room. This is the most deranged thing I've ever seen, with respect to wanting control of a child, and I think it was just that, control. They didn't have it, money couldn't buy it, and threats didn't work, so, they decided to just eliminate what stood in their way.