A pair of rare Peregrine falcons are feared to have been shot dead in Northern Ireland.
Police launched an investigation following the discovery of four abandoned falcon chicks - two dead and two alive - in a nest near Cloughmills in Co Antrim.
A Police Service spokesman said they are investigating the disappearance of the parents but said "circumstantial evidence suggests the birds have been killed."
Peregrine Falcons are recognised as an endangered species and are protected around the world. Police warned if the birds of prey had been shot the culprits would be prosecuted and, under the terms of the Wildlife Order, faced with fines in excess of £60,000 and the loss of their firearms licence.
A substantial reward is being offered for information leading to a successful prosecution.
Mr Jim Wells, a Democratic Unionist member of the Stormont Assembly and keen bird enthusiast, said a terrible act of cruelty had been committed.
"This was the nastiest most despicable incident of persecution of rare birds in Northern Ireland I have experienced in recent years," he said.
"Someone has clearly gone out and shot or poisoned the two adult birds, knowing full well they were leaving the four chicks to die from starvation. We have rescued two birds but unfortunately the other two have died."
Mr Wells appealed for public help in identifying the person or persons responsible and said there was a "substantial" reward being offered for information.