Settle in for this international tale of cryptic shotgun shells on the shores of Scotland that stumped the world's top law enforcement agencies — until a connection with Newfoundland and Labrador unlocked the mystery.
Martin Gray, a self-described beachcomber on the Orkney Islands, Scotland, recounted the supposed true-but-little-known story that started with a man taking a walk on a beach on the Shetland Islands, some 20 years ago.
"He started finding lots of spent shotgun cartridges ... and he gathered up a sample, took it to the local police," Gray told CBC Radio's The Broadcast, noting there were concerns at the time that someone might have been shooting at wildlife.
Gray said nothing else happened with the shells — until a few weeks later.
"There was a problem. Because within the sample of shells he had provided, was a caliber of shell — a 16-gauge, which is a rare, rare gun over here — which wasn't presented on the database of legally-held weapons in the Shetland Islands," he said.
The plot thickens
Ultimately, it was determined that the make of the specific ammunition was not available in Britain. Police even declared an amnesty of sorts, so someone could come forward and help crack the case, without charges being laid.
"There's another side to this — if someone has an illegally-held gun, where are they getting ammunition from? It all started to gather a bit of momentum," Gray said.
Scotland Yard got involved and the organization determined the bullets were made in the U.S. — and were not available in all of the United Kingdom, according to Gray.
A sample of the shells were then shipped to the FBI, where agents deciphered batch numbers imprinted on the shells.
That's when the RCMP stepped to "get to the bottom of it," he said.
"They find that the shells were sold in gun shops in Newfoundland and that they were used in the ... turr hunt offshore," Gray said, noting it was common for people to hunt the migratory seabird.
According to Gray, the cartridges were then likely discarded over the side of vessels and caught up in the current, explaining their appearance on Scotland shores.
Gray said while all the metal parts get corroded away due to the salt water travel, the plastic shell remains intact.
"They're very persistent, they don't decay or rot," he said.
Gray said the intrigue around this particular incident may have diminished when the story unfolded, but that there's still plenty of mystery when it comes to beach combing.
"I enjoy not knowing what I'm going to find ... every day is a blank canvas."