Other researchers, however, proposed different conclusions. Christopher O'Brien, an author and investigative journalist on the subject, said that in his 200 cases of dealing with cattle death, about 40 of those were done by 'something with intelligence'.Christopher O'Brien, an author and who has investigated the subject for decades, said that in his 200 cases of dealing with cattle death, about 40 of those were done by 'something with intelligence'.The FBI told Daily that this was due to the fact that at the time there was no federal law declaring animal mutilation a federal crime, which didn't allow the department to continue investigating.

Instances were reported across the nation but were mostly scattered among South Dakota, Colorado, Kansas, and Nevada.

The news reports make up the bulk of the FBI's 32 page report on the subject, which is prefaced by a brief explanation that their investigation was hindered by a lack of jurisdiction in most cases.

Eyewitnesses often reported seeing beaming lights or suspicious helicopters near where mutilated cows were later found US Senator Floyd Haskell from Colorado pleaded with the FBI to become involved with the mutilations in August 1975 after receiving more than 130 cases in the state alone, and farmers had taken to arming themselves out of fear Supernatural explanations were the only ones that made any sense at the time – given that the technology of the era was not advanced enough to have performed what appeared to be the use of localized lasers.

The areas surrounding the excisions, often around the anus of the murdered animals, had a blackened and burned appearance to them – suggesting the use of a high-powered laser.

And eyewitness reports of strange craft and/or non-human creatures involved with animals.'There was Judy Doraty who in 1973 watched a brown and white calf rise in a pale beam of yellow light.

Inside the craft, she saw tissue cut from the eye, tongue and testicles by two small grey-skinned creatures.On a bright, sunny morning in the summer of 1973, Ron and Paula Watson, two farmers in Springfield, Missouri, witnessed something that changed their lives forever. Their neighbors never believed their story, though one did admit to having one black cow left unaccounted for. They said they saw a 'green, cone-shaped craft' – next to which two 'silver little beings' were standing over a large black cow.'I told Ron, 'My god, they got a cow! But it just laid there and it didn't move.'She described in detail how she saw the aliens running their hands over the cow and then inspecting their long fingers before they 'floated' it into their large ship in the distance.This prompted concerns that the mutilations, nicknamed 'mutes' by those familiar with the subject, were being propagated and covered up by the this image on the left, the cow's heart was excised with expert care - and was the third of three cattle mutilated on the same farm in Missouri beginning in 2011.Theories of who, or what, might be responsible have ranged from satanic cults, aliens, and the government.The most curious aspect is not that the cattle have died, but the way in which they did.