Leading nature charity, the RSPB, have hit out at Dorset Police's decision to drop their investigation into the death of a white-tailed eagle.

Dorset Police launched an investigation earlier this year into the death of the bird of prey, one of 25 eagles that have been released on the Isle of Wight as part of a reintroduction scheme, after its body was recovered in the county.

But examinations and tests on the bird were deemed to be “inconclusive”. While high levels of rat poison brodifacoum were detected, it was not possible to establish if it was a deliberate act of poisoning the bird, police said.

Read more: No further police action into eagle death despite high levels of poison found

The RSPB said it was “completely baffled” by the decision to end the white-tailed eagle investigation prematurely, warning the poison was clearly being used incompetently or with intent to kill raptors, and was an illegal act.

The wildlife charity also said a land search of the estate where the bird was found for evidence of poison baits or misuse had been “recently and unexpectedly called off”.

Responding to the statement from Dorset Police, Katie Jo Luxton, RSPB conservation director, said: “We are completely baffled by the decision taken by Dorset Police to end the white-tailed eagle investigation so prematurely.

“Brodifacoum – the rodent poison that killed the eagle – is highly toxic and it is clear that it was being used either incompetently or with intent to kill raptors. Either way, this is an illegal act.

“A thorough land search had been planned on the estate in question, to look for evidence such as poison baits or misuse, but that was recently and unexpectedly called off.

“The investigation has not been closed by the Health and Safety Executive but that has now been made defunct by the police communication.

“We seek assurance from Dorset Police that their wildlife crime remit is still operational and that other significant ongoing raptor persecution investigations are fully investigated ‘without fear or favour’ as per Police Oath.”