Bones on an Atoll

Human bones had been found on a remote atoll on the Great Barrier Reef after a large driftwood and flotsam constructed word spelling 'HELP' was seen by a tourist plane a long way that day from their usual flight path, however too late for the victim. The case is handed over to the Australian Federal Police as the atoll is over 50 kilometers off the coast and falls into their jurisdiction.
The bones are finally identified via a gold ring found on the atoll that is an induction ring belonging ...