Cambridgeshire Police investigate deaths of 20 swans and ducks
It is understood there were no visible signs of injury
An investigation is underway into how 20 swans and ducks ended up dead in a Cambridgeshrie river.
Seven ducks and 13 swans have been found in a two-mile stretch of the Great Ouse in the past fortnight.
It is understood there were no visible signs of injury, and police said: "Tests have proved inconclusive."
A police spokesperson said officers are keeping an open mind but the most likely explanations are deliberate poisoning or a leak into the river.
The affected part of the river, near St Neots Marina, about 20 miles west of Cambridge, runs alongside a golf course and residential streets.
Pc Alun Bradshaw, from Cambridgeshire Police, said: "It is very unusual for such a large amount of birds to die in such a short space of time and we are keen to find out what caused the deaths.
"I would urge anyone with any information to call police."
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