Slain cattle stripped of certain organs with surgical precision and found in pastures with no trace of blood or evidence have stumped ranchers and law enforcement in quiet farming communities nationwide since at least the 1970s, and potentially for over a century. 

The animals are found in unnatural positions and drained entirely of blood by befuddled ranchers in Minnesota, Colorado, Nebraska, Iowa, Kansas, Oregon and elsewhere.

Sgt. Jeremiah Holmes of the Wheeler County Sheriff’s Office in Oregon, who has overseen five such cases over the past six years, told Fox News Digital that “there’s more questions in this thing than there are answers.”

It is a felony to kill a farmer’s livestock, Holmes said. But there have never been any substantive leads to follow in these cases. The first time the lawman saw an animal die under these circumstances, he said, there was a dearth of tracks or blood in the newly fallen snow.

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He’s spoken to numerous news outlets, researchers and documentarians on the phenomenon, desperate to finally solve the bizarre mystery. 

“Why would someone take a reproductive organ unless it was a ritual or testing? I guess I don’t know,” Holmes said.

“Individuals will reach out and give their theory. Some think its aliens, some think it’s the government doing testing, some think it’s some rancher trying to get even – there are so many theories,” Holmes said. “The only one I have minimized is predators – having grown up in the country . . . and being in the livestock industry, I’ve seen firsthand what a bear will do, a cougar will do, wild dogs will do, even what a man will do. Having seen all that firsthand, there’s no way that I can…chalk this up to predators of any sort.”

Reports of the phenomenon – usually involving cattle, but sometimes involving other livestock animals – began making headlines en masse in the 1970s, with the Colorado Associated Press voting the mutilations the No. 1 story in the state. But records of cow mutilations matching the same patterns date back to 1869, according to “Stalking the Herd: Unraveling the Cattle Mutilation Mystery,” by Chris O’Brien.

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“Investigation Alien,” a Netflix docuseries released this month that follows UFO journalist George Knapp through his investigation of extraterrestrial influence on Earth, suggests that aliens are the culprits. 

“Initially, I grew up very conservative – aliens were something that were scoffed at by my family and friends,” Holmes told Fox News Digital. “Automatically, I assumed they didn’t exist.”

“But what is an alien? If people believe that there is bigfoot or sasquatch, there are people who believe in life on another planet,” Holmes said. “There would be some that would say, ‘if bigfoot is a viable belief, then maybe there are unidentified creatures, even on this earth, that are doing this that we haven’t identified yet.”

Former ranch manager Colby Marshall of Burns, Oregon, found five mutilated bulls over a period of two days in September 2017. 

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“One of the cowboys called me on one of our radios that we had and said, ‘I found a dead bull,’ which was a unique situation, because it was uncommon for a perfectly healthy young range bull weighing 2,000 pounds to just be found dead,” Marshall recalled.

The Hereford bull was lying on its side, with its front legs sticking out at an uncanny angle. Its tongue and entire reproductive organs had been carefully removed – but there was “not a drop” of blood. 

“They had not punctured the abdominal cavity. . . . I’ve harvested a lot of animals myself over the years and butchered a lot of cattle for processing meat, and I’d never seen anything like that at all,” Marshall said.

The second bull was found with the same organs missing, as were three more bulls found the next day.

“I’ve seen lots of animals dead in a variety of different situations from injuries or diseases or what have you,” Marshall said. “It was just the most surreal, weird situation for livestock that I had ever experienced.”

Holmes told Fox News Digital that, because ranches are sprawling, and cattle mutilations typically take place in remote areas, necropsies and other forms of investigative work are no longer viable, because the animals’ bodies have become degraded by the time they are found. But in Marshall’s case, the corpse was relatively fresh. 

“We tried to collect the forensic evidence the best we could, and we necropsied the bull,” Marshall said. “There were no signs of liver damage or heart damage or lung damage. There was no missing internal organs. The [stomach] of the animal was full. They had been eating. They had been drinking. They had not been any stress to them at all.”

The bulls who weren’t transported to a lab just “melted into the ground” –  scavengers wouldn’t touch them, Marshall said. 

“In a normal situation, the scavengers, the coyotes, the bears, you know, it would just sort of tear the animal apart, drag it all over. Bones would be spread all over, hides would be missing, heads would be gone,” he said.

A $25,000 reward was levied for any information that led to the capture of the person or persons who mutilated the bulls – but no information ever came, Marshall said.

Like Holmes, Marshall is willing to speak to anyone on the topic in the hopes that “the longest-running murder mystery in the history of the world” is solved, including other puzzled ranchers throughout the country.

Rather than extraterrestrials, Marshall thinks a sophisticated network of humans – likely cultists or a group using the animal parts for ritualistic purposes – is to blame. 

“I believe that there is a big galaxy out there. . . . And there’s an extremely high probability that we’re not the only sentient life forms in the galaxy. I believe that, yes, there probably is aliens out there. And, you know, they’ve probably visited Earth,” Marshall told Fox News Digital. “Now, do I think they’re using their technology to come after free-range bulls in eastern Oregon? No, I don’t – I think they would have better uses of their technology than that.”

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“But hey, if they are coming across the galaxy to come and get beef in eastern Oregon, that means we’ve got pretty darn good beef and maybe the best in the galaxy,” Marshall quipped.

“I don’t mind talking about it and telling the story,” Marshall said. “I just want people to be aware that. . . there are other people out there that have experienced it. And the thing that we need to do is we need to talk about it because maybe that’ll bring light to it, and maybe we could get some answers.”

The FBI investigated the phenomenon of animal mutilations between 1974 and 1978, according to its website, but was unable to find any answers.

“I’ve been advocating for the federal government to look into it more with the tools that we have now,” Holmes said. “We have a lot more tools since the 1980s to investigate . . . the reason why I’m a little more vocal about this is because I want it solved . . . and I know we’re not going to be able to solve it on our own.”