Police are appealing for information after a protected bird of prey was shot.
The RSPB were called to recover the dead peregrine falcon from Brayford Pool in Lincoln on February 22.
At the time it was unclear how the bird died, but post mortem results are now back from the Predatory Bird Monitoring Scheme at Lancaster University, who have confirmed that it was shot.
A total of 10 shotgun pellets were found inside the carcass.
The peregrine is afforded the highest degree of legal protection under the Wildlife and Countryside Act of 1981.
Breaking this law can lead to fines of up to £5,000 and a prison sentence of up to six months.
Lincolnshire Police wildlife officer Nick Willey said: “It is unlikely that someone actually fired a shotgun in the Brayford Pool area so it could have been shot upstream and been carried by the current and we know that the carcass was in pretty good condition, so it hadn’t been dead long when it was found.
“The post mortem has shown it was a female juvenile – less than a year old.
“We don't think that it is one of the birds from the Cathedral but it is clear that this was a concerted effort to shoot and kill a rare and protected bird of prey which I find absolutely despicable and I hope somebody has enough sense to ring in with information to the offender or offenders."
Senior Investigation Officer for the RSPB Duncan McNiven said: “It’s shocking that such a fantastic bird of prey has been gunned down like this not far from where hundreds of people have taken immense pleasure from watching them around Lincoln Cathedral.
“Unfortunately, peregrines continue to suffer sustained persecution at the hands of elements within the game keeping, pigeon fancying and falconry community which has resulted in the species recently being added to the National Wildlife Crime Unit’s wildlife crime priorities for 2011-12.
“The RSPB fully supports the police in its efforts to track down the perpetrators and we appeal to anybody with any knowledge of this despicable crime to come forward”.