The bird of prey was found on July 4 in ill health in the Fish Dam Lane area, near Carlton Marsh, and died a short time later.
As the falcon was a juvenile, it is likely that it was born this spring.
Initial assessments showed it could have been poisoned, and following a forensic examination by the Wildlife Investigation Scheme it has been confirmed the falcon had been poisoned with Bendiocarb a highly toxic substance.
Investigating officer PC Fran Robbs De La Hoyde said: “It is believed the poisoned peregrine falcon ingested bait laced with the poison which was deliberately set out to target the bird.
“There is nothing to suggest that this bait was laid in open land.
“This was a deliberate act that caused the death of a beautiful and protected bird. I am saddened by this and I am asking for help to bring those responsible to justice.”
Peregrine falcons are protected under the Wildlife and Countryside Act 1981, and the poison used to kill the bird is one of the most common to kill birds of prey.
To intentionally kill or injure one is a criminal offence and could result in a unlimited fine or up to six months in jail.
Tom Grose, of the Royal Society for the Protection of Birds (RSPB), added: “It’s always a privilege to catch a glimpse of a peregrine.
“The fastest birds in the world, they are highly adaptable creatures and often make their homes in urban areas these days.
“Bendiocarb is one of the most commonly abused substances for killing birds of prey and we have sadly seen it used for this purpose on many occasions.
“It is illegal to kill these birds, and we urge anyone with information to come forward.”
The poisons that are most commonly used to commit crimes like this are incredibly toxic and harmful to humans and pets if you find a dead or injured bird you are strongly advised not to touch them.
Luke Steele, spokesperson for Ban Bloodsports on Yorkshire’s Moors, said:
“The continued persecution of birds of prey in Yorkshire is outrageous.
“It is a stain on our county’s proud reputation, with wildlife—including birds of prey like peregrine falcons, buzzards, red kites and hen harriers—being part and parcel of what makes Yorkshire such an amazing place to be.( “We unreservedly condemn illegal persecution of birds of prey.
“It is starting to have a damaging impact on tourism and undermines the work of law-abiding landowners who are actively working alongside us to improve prospects for all forms of wildlife in the area.”
If you have any information, contact 101 and quote crime reference number 14/104692/20.