It is a mystery - some would say a murder mystery - but the clues are unable to lead us to a clear killer, even though the body count has been unprecedented over the last two months.
This week statistics revealed by a local volunteer recorder working for the Scottish Marine Animal Stranding Scheme (SMASS) reveal that over only six weeks 25 bodies of marine mammals have been washed up on the shores of the Outer Hebrides.
Many of the remains, found by volunteers and members of the public taking to the region’s beaches over the summer, were not in good shape but from those that could be examined they have all been identified as Cuvier’s beaked whales.
This is a species normally found well off shore in deep water, diving to extraordinary depths of up to 7,500 feet to feed on squid.
Between 1913 (when the British cetacean stranding reporting scheme started) and 2003, no more than five Cuvier’s beaked whales were reported in the Outer Hebrides in each decade; between 2003 and 2012 the number was 18, but five of these were found within two months early in 2008.
So, 25 found along the coastline of the Long Island within six weeks is unprecedented. And there are reports of more - believed to be 40 animals altogether - across the west coast of Scotland in Islay, Mull, Iona, Coll, Tiree, Skye, Ardnamurchan and Kintyre.
Most of the animals have been reported to the SMASS.
This organisation has been in operation since 1992 and is part of the Cetacean Strandings Investigation Programme, funded by the Scottish and Westminster governments.
The project aims to provide a systematic and coordinated approach to the surveillance of Scotland’s marine species by collating, analysing and reporting data of all whales, dolphins and porpoises (collectively known as cetaceans), seals, marine turtles and basking sharks that strand on the Scottish coastline.
The SMASS report for 2016 details that between January 1st to December 31st there were 668 reports to the scheme comprising 404 seals, 263 cetaceans, one basking shark and one marine turtle.
Of these, 63 cases, comprising 50 cetaceans, 12 seals and one turtle were examined to establish a cause of death and a further 52 animals comprising 41 cetaceans, 10 seals and one basking shark were sampled by trained volunteers.
Their work is often able to establish the cause of death such as attacks by other animals, but in the case of the latest strandings in the Western Isles the explanation for the deaths of so many within such a short time frame remains a mystery.
There has been speculation in the past that sonar activity can disturb these animals, but with many of the bodies in too poor a state to conduct post-mortems it is unclear what has caused this current spate of fatalities.
If you find any dead whale, dolphin or porpoise on the shore please get in touch with SMASS on 01463 243 030, or 07979245893 - or email them at firstname.lastname@example.org , with pictures if possible, the location and the date.
They will ask local volunteer recorders to send measurements and samples; very fresh animals may have a post mortem.
It’s better to have several reports of the same animal than none at all.
Live animals should be reported to the SSPCA 03000 999 999 or British Divers Marine Life Rescue 01825 765 546.
It is advised that people should avoid direct contact with any dead animals as they may carry bacteria or viruses that can be harmful.