A fourth dead whale has been washed up on the beach near Skegness, taking the number found along the east coast to five.
The whale, thought to be from the same pod as those found at the weekend, was discovered by a member of public, five miles south of Skegness where one was washed up on Saturday and two more beached on Sunday.
Another whale was found on Hunstanton beach on Friday night.
The whale in Wainfleet was spotted by a member of public this afternoon.
A spokeswoman for the Maritime & Coastguard Agency said: “We can confirm there is a fifth whale and it is in Wainfleet. We have informed our Receiver of Wreck and the Zoological Society of London.”
It is believed to be not easily accessible and on Ministry of Defence (MOD) land and is not expected to be dealt with by the local authority.
Crowds gathered on the beach in Skegness as autopsies got under way on the three dead sperm whales. People were shocked to see one of them graffitied with the letters CND and a peace symbol.
The word "fukishima" has also been sprayed on a whale’s back.
Police visited the scene but are not looking for the culprits.
A spokesman said: "It’s a terrible thing for someone to do, but there wouldn’t be an actual criminal offence."
Coastguard teams are monitoring the situation and keeping the general public away from the whales in the interests of safety
Mike Poplett, watch manager for Humber Coastguard, said: "Graffiti is normally criminal damage but the whales don’t belong to anyone so unless the graffiti was very offensive and constituted a public order offence, there would be no offences."
Witnesses also said maritime biologists were using a probe when there was a “huge blast of air”.