What happens to a house after a massacre occured in it?

Let's say an insane person breaks into a house and kills the family living there. Obviously blood and the like gets everywhere. Police eventually arrives and takes the corpses away. What then? Okay, if they have living relatives, they probably inherit the house, but they obviously don't want to scrub up the blood of their dead loves ones. Are there cleaning companies that do this? If the house gets into the government's hands, do they just leave it in its gory state?