A beagle returned home with an unusual find that has led to a criminal investigation in the town of Gallup, New Mexico: a human skull.

The dog found the remains Saturday evening and carried them home. Its owner, who lives on the west end of Gallup’s airport, then alerted authorities, John Allen, deputy police chief, told msnbc.com.

Police have determined the skull was from an individual believed to be a man, roughly 35 to 45 years old, who probably died about three years ago, Allen said.

Police decided to search a field around where the beagle lives since they figured the canine couldn’t have walked too far with the skull due to the dog's size. Their search turned up other human bones that “we believe are related to this skull,” Allen said.

“It is a criminal investigation at this time and until we determine otherwise, or receive other information, we’re going to continue along this path,” he said. “We’re attempting to identify who this individual may be … we may possibly have a lead and we’re looking into that right now.”

Gallup Police Det. John Yearley said dogs and coyotes unearth human remains a few times a year. In one case last year, dogs found bones that led police to a homicide case.

Police put the beagle on a leash to see if it could lead them to more remains, but the dog didn't, Yearley said. More bones were found near a coyote den, said Yearley, adding that he believed the body had been buried.

Of the beagle, he said, it is "quite the rabbit hunter. How he switched off from rabbits to the skull, I don't know."

Beagles have the best ground scenting ability among popular dog breeds, a trait that made them popular rabbit hunters in centuries past, according to SPCA International.

Gallup is a rural area that is home to about 20,000 people and borders the Navajo reservation, Allen said. It is about 140 miles west of Albuquerque.

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Megan Leavey

Marine Cpl. Megan Leavey with Sgt. Rex, a dog trained to detect explosives, contraband and bombs. The photo was taken in Ramadi, Iraq, in 2006.

Marine Cpl. Megan Leavey gave a lot for her country, and so has her favorite comrade — Sgt. Rex.

The dog handler and the bomb-sniffing German shepherd Rex served together for more than three years and through two deployments until a roadside bomb blast in Ramadi, Iraq, in 2006 took them out of commission. Leavey, now recovered and discharged from the Marines, is battling to adopt her old canine-in-arms.

"Rex is my partner; I love him," said Leavey, 28, who lives with her father in Rockport, New York, and works as a dog handler. "We have been through so much together … I’ve spent day and night with this dog. It’s a very strong bond."

But the dog's discharge has proved more complicated than her own. Leavey first applied to adopt Sgt. Rex as she was completing her Marine Corps service in 2007. She did all the paperwork, she said, but the military determined the dog had recovered completely and was still fit for work, and has continued up to now.

Sgt. Rex has become something of a celebrity along the way, featured in a 2011 book by his first handler, Mike Dowling, called "Sgt. Rex: The Unbreakable Bond between a Marine and his Military Working Dog."

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But Leavey kept tabs on her old friend, receiving regular updates and pictures from personnel working at the kennels at Camp Pendleton, Calif.  About a month ago, she said, they let her know that Sgt. Rex, now 10, had developed facial palsy, which was affecting his equilibrium.

"Now he is ready to be retired," said Leavey, who quickly filed her paperwork to adopt the dog.

But that determination — like most things in the military — is subject to some procedures.

"An official request for retirement has been submitted," said Matthew Stines, press officer for the Air Force, which has jurisdiction over the Military Working Dog Program, when reached on Friday. He said that action on that request is expected to take about two weeks. 

Then the dog will be evaluated for "adoptability" at Camp Pendleton. If he is approved, the final determination for his release would then be made after consideration at Lackland Air Force Base in Texas. Stines said he did not know what would happen if the dog was determined to be unsuitable for adoption, nor how long these evaluations were expected to take, though he promised to look into it.

"(Rex) is just hanging out in his kennel," Leavey said. "I know the Marine Corp has other more important issues. But it’s important to me. And he deserves it."

Frustrated by the bureaucracy, Leavey has recruited a high-powered champion — Sen. Charles Schumer, D-N.Y., who wrote to Air Force Secretary Michael B. Donley to urge expeditious handling.

"Marine Corporal Leavey and Rex are true American heroes who saved countless American lives uncovering roadside bombs and booby traps in Iraq," Schumer said in a statement issued Friday. "I’m strongly urging the Air Force to do the right thing, cross the T’s and dot the I’s so that Rex gets the home he deserves, and Corporal Leavey can be reunited with her faithful companion."

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