1) They have a criminal background, a background of assult of people that would NOT look good if it ever went to court, esspecually if the court/police/jury found out now that most of these past assult victums were now dead
2) The guy they beat half to death, has some dangerous connections in law enforcement (shady, theiving cop is uncle)
3) (as of now in the story) The friend who was abused and raped, the guy who did it was her boyfriend, and she is still refusing to admit any abuse happened and is currently at the moment still on her boyfriends side.