About two dozen cows have been found dead over the past few days in Navajo County.

Law enforcement has ruled out foul play. David Clouse with the Navajo County Sheriff's office say the current suspect is "naturally occurring ecological poisoning."

“The way the grasses come from either an extreme drought or heavy rain," he said. "There's some certain weeds that can come grow and they have a poison that the cows just don't take a liking to and can kill them.”

Arizona Game and Fish and the U.S. Forest Service are still investigating and a toxicology report will be released soon.

This isn’t the first time the state has seen similar cow deaths, but it has been about a decade since the last incident.