Updated

A search for a 4-year-old New Mexico boy led authorities Sunday to a deep, narrow hole in a neighbor's backyard where a police spokeswoman says a detective located the body of a child.

Carlsbad police said they are fairly sure the body is that of 4-year-old Samuel Jones, who was reported missing Saturday from his home next door and who was the subject of an Amber Alert issued late Saturday.

"We have reports of one missing child, and this child is right next door to the missing child's house," police spokeswoman Lt. Jennifer Moyers said, while adding that authorities cannot be positive the body is Samuel's until the body is retrieved.

Efforts to recover the body began Sunday afternoon, with a large tracked excavator on scene along with metal shoring typically used in pipeline construction projects.

A renewed house-to-house search had just started shortly after daybreak Sunday morning when a detective found the 14-inch-wide hole in the backyard of the home next door to Samuel's house, Moyers said.

The detective shined his flashlight down the hole and saw what appeared to be a body dressed in clothing Samuel was last wearing, Moyers said. Searchers later sent a camera down the hole and confirmed a child was about 30 feet down. Temperature and oxygen levels were later taken and showed no signs of life.

"The conditions are not favorable, not survivable," Moyers said.

The boy's mother and father were told of the discovery and were at the scene.

There is no indication of foul play, and police know of no history of child abuse at the home, but detectives are treating the case as a homicide as a precaution, Moyers said.

Samuel lived in the home with his parents and two older siblings, a boy and girl ages 6 and 7, Moyers said. Some young cousins were at the house Saturday when the boy was last seen playing in the yard.

The rural neighborhood is a mix of homes and vacant lots, and a 4-foot chain link separates the boy's home from his neighbor's. It's possible the boy could have climbed the fence and simply fallen into the hole, which was dry and may be deeper than the 30 feet where the body was wedged, Moyers said. There are no curbs or sidewalks in the neighborhood on the city's south side.

Getting the body out will be a long process, Moyer said. A specialized search and rescue team from Roswell was headed to Carlsbad at midday to oversee the operations.

"It's a little tricky in that you have to start to dig kind of away from the hole and dig at a slant until you get down deep enough to go laterally," Moyers said. "They're going to have to put in retaining so that the dirt doesn't cave in on what they've dug out."