A dead porpoise which washed ashore could have been killed by a seal, an expert said.
The body of the aquatic mammal was found at Nacton, near Ipswich, on Sunday.
HM Coastguard has removed the carcass from the River Orwell estuary for further investigation.
Rob Deaville, of the UK Cetacean Strandings Investigation Programme, said a working hypothesis was that it had been attacked by a seal.
A post-mortem examination is due to take place later this week.
Mr Deaville, who manages the Zoological Society of London project, said he needed to take a look at the body, but from pictures he had seen there appeared to be injuries which could have been caused by a grey seal.
He said: "It may have been an interaction with a grey seal.
"It has happened in the area before."
Mr Deaville said seal bites can become infected which can lead to death.
The programme is also examining a porpoise which washed ashore at Winterton, Norfolk, recently.
On Saturday afternoon, rescuers attended to a porpoise that had become stranded on the mud in Hamford Water, between Walton-on-the-Naze and Harwich in Essex.
They helped to move the porpoise to a better location and it was successfully refloated.