Swan and duck deaths on River Great Ouse investigated
Twenty swans and ducks have been found dead on a stretch of river in Cambridgeshire in the past two weeks, police have said.
The birds were found along a short stretch of the River Great Ouse between Paper Mill at Little Paxton and St Neots Marina.
Tests on the 13 swans and seven ducks have so far proved inconclusive.
They had no obvious injuries and the Environment Agency said tests found no pollution in the water.
A Cambridgeshire Police spokesman said it was "very unusual for such a large number of birds to die in such a short space of time".
The force has appealed for information about the birds' deaths.