The finest specialists in British archaeology have confessed themselves baffled by the mysterious case of the dead 19th-century Pacific walrus found buried in a London graveyard.

The remains of the deceased, 12-foot-long pinniped - which may have weighed as much as two tons when alive - were discovered in a coffin interred in a St Pancras graveyard during excavations for a new railway terminal. This was actually some time ago, but today we learn that investigating archaeologists, having finally given up on unravelling the mystery intercontinental dead-walrus-by-gaslight affair, have placed the animal's remains on display in a Hackney museum.

In a macabre twist, it seems that the massive tusked sea mammal shared its coffin with a mixed array of human bones including skulls, some pierced as though by a sharp tool - or tusk.

It's thought that scientific or medical research may have led to the grisly mixed burial. Rather than some Lovecraftian tale of a horrific walrusoid abomination - created perhaps in the lab of some insane experimenter, only to break free and terrorise the foggy streets of old London town in a bloody campaign of tusky or red-flippered slaughter, then later to be buried along with its victims' remains - the experts suspect medical students. The dissection of human cadavers for medical education was made legal in 1832, apparently, and with the practice having been legitimised it became more common to give the bodies a proper burial after the tyro medics had finished with them.

However the said corpses would often by this point have been dismembered into quite small parts. Meanwhile generalised anatomical and biological research would have been taking place, sometimes in the same labs or facilities, which might easily have seen exotic creatures such as the walrus - in this case perhaps brought back from the Pacific by long-haul whalers as a curiosity - carved up in the name of science.

It's possible that a job lot of medical-training and scientific remains was buried in one go, therefore, so accounting for the curious mixture of body parts and species found in the St Pancras coffin. Alternatively some kind of hilarious medical undergraduate cadaver-themed prank may be to blame.

“It’s a bit of a mystery,” confesses Phil Emery, the discoverer of the coffin, talking to the Times. “We did some research ... but we drew a blank. There was a reference to Prince Albert riding on the back of a giant tortoise, but unfortunately it wasn’t relevant."

The walrus bones are now on display at the London Archaeological Archive and Research Centre in Hackney. ®