Arthur W. Upfield 
The Mystery of Swordfish Reef [EPUB ebook] 

On a calm October day in an Australian seaside town, three met set out to sea for a day’s fishing… and do not return. Despite intensive searches, no trace or the men or their boat is founds, until weeks later, a passing trawler hauls in a gruesome catch – the head of one of the missing fishermen. It is clear that its owner was murdered with a pistol shot, but by whom, and why, is for Bony to find out.