A wide scale-investigation involving police and several other organisations is being carried out to discover why more than 35 badly scarred seal carcases have appeared on the north Norfolk coast.

A wide scale-investigation involving police and several other organisations is being carried out to discover why more than 35 badly scarred seal carcases have appeared on the north Norfolk coast.

The mysterious deaths have been occurring in Wells, Blakeney and Morston since December and have been continuing over the last few weeks.

The animals, a mixture of both grey and common seals, have all suffered laceration-type injuries which are believed to have proved fatal.

All have a single smooth-edged cut that starts at the head and spirals around the body which is believed to have been caused by a blade of some sort. Post-mortem examinations have been carried out on two seals but the results are not yet known.

Seal biologist Dave Thompson, who works for the Sea Mammal Research Unit in St Andrews, Scotland and is assisting the investigation, said: “There have been a few unexplained seal deaths with identical injuries off the coast of Fife over the last couple of years but nowhere near the number in Norfolk. I've been in this career for more than 20 years and I've never seen such a large number of seals suffering this same injury over a relatively short period of time, and we do not yet know what the cause of these injuries is.”

The investigation involves Wells Police, the National Trust, Sea Mammal Research Unit, The Marine Management Organisation, RSPCA, Natural England, National Wildlife Crime Unit, Eastern Sea Fisheries, the Veterinary Laboratories Agency and the Norfolk Wildlife Trust.

Police inspector Mike Brown said: “The seals have suffered awful injuries which we believe are the probable cause of death and there is no indication that these were caused by disease or any type of predator.

“We have been working closely with seal boat operators and local fishermen but would like to hear from anyone else who may have information regarding these occurrences.”

Several theories have been circulating locally including that recently spotted large bull seals may be responsible or that the seals have been accidentally caught up in boat propellers when looking for food.

But Dr Thompson said: “The injuries do not appear to be consistent with propeller strikes. They would appear to be caused by some sort of rotating single blade within a channel or cowling or by the seals rotating past some form of static blade. And they were almost certainly killed shortly before they were found and within a few kilometres of where they were washed ashore.”