Murder Down Under (An Inspector Napoleon Bonaparte Mystery)

From back cover: Bony is the sort of detective who enjoys nothing better on a holiday than a little informal investigation. When he agrees to help a colleague in the matter of the disappearance of George Loftus, a farmer whose car was found wrecked near the world's longest fence in the wheat country of western Australia, he cannot immediately find evidence of the murder he suspects. Loftus's wife seems concerned about him, but his handsome hired man is an enigma. It is not until Bony becomes absorbed in the second mystery of Mr. Jelly, an amateur criminologist who himself often disappears on secret business, that he finds the key to the strange goings-on in this seemingly ordinary farming community.