"Big cat" sightings reported to Police Scotland and Scottish Government have been revealed after an FOI request.
The correspondence detailing reports of mysterious large felines between police officers, the Scottish Government and other official bodies has been released.
Police probed a spate of killings in 2016 with sheep carcasses stripped of meat in a way which didn't resemble fox or bird attacks. Some three to four sightings of a big cat were recorded by one officer.
Scottish Natural Heritage (SNH) recorded a description of a big cat 'the size of a Labrador' which killed 36 sheep between August 2015 and January 2016. It was described as 'black or black/brown depending on the light' and 'Panther/melanistic leopard'.
An 86-page dossier was released by the Scottish Government, showing tooth prints were closer in size to a wolf than a lynx.
A document said: "A wolf would be 45, 14 and 28mm respectively. Most of the images depict sheep that have been partially eaten and it is difficult to make out that sort of detail.
"However, image IMG0521 shows the remains of the thoracic cavity with what appear to be lacerations from canine teeth between the ribs - clearly from a large carnivore. Estimating roughly from the photo, I would suggest these are between 40 and 50mm apart."
In 2017, Scottish Wildcat Action suggested the cat may be a hybrid which was unneutered.
An email said: "We believe it to be the same hybrid that Roo Campbell caught during his study in 2013/14 which you previously analysed as 80% wildcat so it's great to have that confirmed.
"She is a black cat with stripes visible in infrared.She bred this year and produced two black kittens."
The haul of new evidence was obtained by the creators of new documentary film 'Panthera Britannia Declassified' which is set to be released online soon, before having a television premiere later this year.
The filmmakers sat on the evidence for over a year, before determining that it was "too controversial" to include in their documentary.
The email chain shows a detailed discussion of a spate of recent "savage" livestock killings, with photographs of a young calf which had its tail torn off by a predator that only left a number of claw marks which could not have been left by a fox or a dog.
In another case from November 2018 experts had found the carcass of a dead ewe which had been dragged 20 yards "up a rock face".
The ewe had "two puncture marks on the front of her right shoulder and two at the back", and "the wounds were over three inches apart".
A police official agreed with a wildlife expert that they are "inclined to think" this was the work of a cat.
An email from Stan Whitaker, non-native species adviser at Scottish Natural Heritage, said: "If it's a big cat in the wild, which are fortunately very rare, its covered by the Dangerous Wild Animals Act 1976 and the Wildlife and Countryside Act 1981.
"Again, needs to report it to Police Scotland on 101, as there is a risk to livestock and people."
In 2011 an email noted "police has issued a public statement about the possibility of a dangerous animal on the loose in Sutherland, following a spate of recent attacks on livestock."
Gory images showed a calf with its tail ripped off, and savaged sheep. The document proposed that if big cats did exist, darts should be used to euthanise them "for political reasons".
An email titled 'big cat call from Police' by a Scottish Natural Heritage officer, read: "Get the species ID first. Then if non-native there's no protection by law ( they can shoot it) but may wish to consider darting etc for political reasons.
"If protected species, they can ask for licence."
In 1983, Royal Marines were dispatched to Devon for several weeks to hunt and kill a creature which became known as the 'Exmoor Beast'.
And in 2003, armed police were sent into the Welsh mountains for a stake-out which lasted days, after an officer witnessed a farm dog being eaten by a big black cat and a survey carried out by expert animal trackers revealed that up to seven different individual big cats could have been at large in the region at the time.
A spokesman for the documentary makers said: "Any "concerns for public safety" linked to big cats on the loose were glossed over with the reassuring sentiment from one detective inspector who said he was "happy that there's not an imminent risk to public safety if it's well fed".
"But without reliable and accurate data on the number of big cats at large and precisely how well fed they are, this might do little to reassure anyone."
A Department for Environment, Food & Rural Affairs' (DEFRA) responded to a separate Freedom of Information request and said they "do not hold any records of big cat sightings or encounters in the UK".
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