While excavating a Las Vegas backyard for an in-ground pool in late April, workers made an unexpected discovery: bones buried about four to five feet underground.

The foreman arrived at the home a few days later with crime scene investigators.

Homeowner Matthew Perkins only learned of the discovery when Las Vegas Metropolitan Police Department showed up at his house to investigate. Police determined the bones were not human remains and left it up to the homeowners on how to proceed.

'[The police] came in, dug up the bone, saw that it was fairly large and at that point told us, 'Too big to be human. Not our concern anymore,'' Perkins told CNN. Once his backyard was stated not to be a crime scene, Perkins was still curious about the bones they had discovered, so he decided to halt construction of the pool until the bones could be fully excavated.

Perkins reached out to paleontologists at museums and universities but none returned his calls.

A local news agency put him in touch with Nevada Science Center paleontologist Joshua Bonde. Bonde told news channels that calls like this are common and most findings are not significant, but this time was different.

Excavators have so far turned up bones from the animal’s legs, ribs, vertebrae and a jawbone with teeth and believe that the animal was likely a prehistoric horse.

Based on the layers of rock surrounding the bones, paleontologists estimate the remains are between 6,000 and 14,000 years old. Two species of horse lived in that area at the time, both of which became extinct in North America at the end of the last ice age.

According to Bonde, the fact that the skeleton was intact suggests that when the animal died, it was quickly covered up, probably by mud, preventing scavengers or flowing water from stripping the remains.

“It was an actual skeleton,” Bonde told the Review-Journal. “The bones were in the leg position attached to one another, which is actually really rare preservation for that area.”

Perkins’ property is about three miles away from the Tule Springs Fossil Beds National Monument, a famous site for ice-age era fossils. Present day Las Vegas was once a marshland and home to a variety of animals including mammoths, saber-toothed cats, camels, wolves and other now-extinct mammals, Bonde said.

Bonde said the U.S. has laws that fossils discovered on private property belong to the property owners. Perkins says he will likely loan them to the Nevada Science Center to study it, preserve it and put it on display for others to enjoy.