PRINEVILLE, Ore. (AP) — Cattle in Oregon are again showing up dead under strange circumstances.

Over the past three months, seven animals have been found mutilated on ranch land in central Oregon’s Crook County, the Northwest News Network reported. In most cases, the dead animal’s sex organs, tongue or eyes are cut away cleanly and there is no blood.

The cases call to mind similar discoveries of five mutilated bulls in 2019 in Harney County, where five bulls were found dead in a 2-mile radius with their sex organs and tongues removed. There have also been cases in recent years in Wasco, Umatilla, Wheeler and Lake counties in recent years. There have also been cases reported in Arizona.

Similar cases of mutilated livestock and even elk and deer have surfaced periodically across the country and, in the 1970s, a rash of livestock mutilations across the U.S. West and Midwest struck fear in rural areas.

Thousands of cattle and other livestock ranging from Minnesota to New Mexico were found dead with their reproductive organs and sometimes part of their faces removed.

In the current Oregon cases, the sheriffs from several affected counties are trying to coordinate and share information, the network reported. Harney County in 2019 also worked with the Oregon State Police to try to crack the mystery.

The theories range from scavengers such as carrion bugs eating the carcasses to people attacking the animals to cause financial harm to ranchers.

“It’s upsetting, because, again, it’s our livelihood. It’s how they make their money and how they feed their families and support themselves,” Crook County Undersheriff James Savage said of the ranchers who lost animals most recently.

Savage said in such a vast, rural county it’s hard to solve such cases — and there’s very little physical evidence.

“In a lot of cases we come down, it’s a burglary or theft or whatever,” he said. “We have suspects. We catch something on camera, or someone sees something, or witnesses something. But this is so rural, it’s just very tough to piece it together.”