Open and shut

Before exiting the scene of carnage, Rufus had arranged the positions of the bodies to look like his father had given the woman a severe beating plus maybe a kinky sexually-motivated partial strangling, going horribly wrong when she produced and used the knife on the man.

Police should think them open and shut cases of murder and self-defence. No-one else involved.

A pity the poor woman had to be sacrificed, but Rufus wanted no witnesses. Besides, she would probably have gone on to shack up with another brute, so she was well out of it, he thought.