Dog walkers and countryside users are being warned about a dangerous banned poison being used in bait to target birds of prey in North Yorkshire.
A red kite was found dead close to Pateley Bridge in March and tests have shown traces of Bendiocarb and the banned poison Isofenphos.
North Yorkshire Police are warning anyone who may find a carcass of a bird or rabbit not to go near it.
The county had the highest number of offences against birds of prey in 2018.
Officers said the kite was found close to a caravan site near the Nidderdale town and submitted to the Wildlife Incident Investigation Scheme.
Analysis of the bird showed the two pesticides were present and concluded these were responsible for the death as it was otherwise fit and healthy and had died soon after eating a large meal.
North Yorkshire Police said: "Bendiocarb is licensed for use as a pesticide in England, but Isofenphos is banned in the UK.
"Both pesticides are highly toxic and their use has previously been identified as the likely cause of death of other red kites in North Yorkshire.
"Despite extensive investigations, police have not been able to find evidence to understand how the pesticides reached the red kite or to identify those responsible for misusing these toxic substances."
In August the Royal Society for the Protection of Birds' (RSPB) annual report said birds of prey were being subjected to "relentless persecution".
The highest number of recorded offences, 15, took place in North Yorkshire.
Police have urged dog walkers to be vigilant and not let pets "eat or investigate any animal carcasses they might come across when out walking".
"If you find any evidence of bait like this or a poisoned animal, then do not touch it. Many chemicals are extremely toxic and can be absorbed through skin," the force added.