A “cruel” killer deliberately drowned a dog by tying a bag full of bricks around its neck and dropping it into the river in Spalding.
The little Staffy-type dog was discovered on Sunday.
It had a red collar.
A Lincolnshire Police spokesperson said: “We are left wondering who would do such a cruel thing. There are plenty of charities and organisations that would have looked after and re-homed the dog.
“If anyone has any information as to who owned this dog or who has done such a despicable cruel act, please contact us or the RSPCA.”