One half of a rare breeding pair of golden eagles has been killed by poison in the Scottish Borders.
The bird was found on Sunday and tests have confirmed that the banned substance carbofuran was involved.
An investigation was launched by police and wildlife charities after the eagle was found on a grouse moor in the Borders.
The Scottish RSPB has offered a reward of £1,000 to anyone who can help provide information about the case.
A poisoned bait was also discovered near the eagle but tests have yet to confirm what substance was involved.
Although the golden eagle's chick has fledged it would still expect to be fed by both of its parents.
The victim is thought to have been a female bird about 10 years old which had been using a long-established nest site.
Bob Elliot, head of investigations at RSPB Scotland, said it was a great loss to the area.
"Sadly, illegal persecution of birds of prey continues to be a shameful fact of life in parts of Scotland in the 21st Century," he said.
"Now, after nine or 10 years together, the Borders has lost its only breeding pair of golden eagles.
"We hope that by offering a reward, a member of the public will help the police to catch the perpetrator and bring them to justice."
Lothian and Borders wildlife crime officer, Pc Mark Rafferty, said the incident showed that indiscriminate use of poisons was "alive and well" in the area.
"This incident goes to show that people are still willing to take this risk, and the result is that one of Scotland's finest birds has now been destroyed," he said.
"This is criminal behaviour, and I'd ask for the public and particularly the gamekeeping community to come forward with information on this or any illegal wildlife crime."
The poisoning has caused concerns for the future of the golden eagle's chick.
"The various agencies concerned are sickened at the mindless poisoning of the female golden eagle found on a grouse moor," said Ch Supt Mike Flynn of the Scottish SPCA.
"Scotland has lost one half of the only breeding pair in the Borders and this could ultimately result in a second tragedy as it is unclear if the chick will survive."