Arthur W. Upfield 
Venom House [EPUB ebook] 

The Answerth family’s mansion seems to deserve its nickname of Venom House — perhaps because of its forbidding setting, an island in the centre of a man-made lake, its treacherous waters studded by the skeletons of long-dead trees. Perhaps it’s because of the unquiet ghosts of the Aboriginals slaughtered by the Answerth ancestors. Whatever the reason, most people are content to give Venom House and its occupants a wide berth… until a couple of corpses turn up in the lake. Inspector Bonaparte has a sudden urge to get to knows the Answerths and their charming home much better…