DELTA, Utah — About 100 pieces of charred wooden chips were uncovered Saturday as investigators dug through what they have described as a shallow grave during their search for evidence in the disappearance of a missing mother.
Authorities suspended the digging at a site in the rugged Utah desert and said it would resume Sunday. They are searching for the remains of Susan Powell, who disappeared on Dec. 7, 2009.
At least seven cadaver dogs have positively indicated that there might be human remains buried at the site, NBC station KSL of Salt Lake City reported..
But three days of digging have turned up no evidence of remains. On Saturday, investigators uncovered blackened pieces of wood ranging from dime to golf-ball size, KSL said.
The wood chips were being brought back to Salt Lake City for further examination.
"They obviously have some type of human decomposition on them because that's what the dogs are hitting on," West Valley City Lt. Bill Merritt said.
But police have had to backtrack on such statements before. On Wednesday, they said they found human remains but later backtracked, clarifying that cadaver dogs had alerted them to the site but no remains had been found.
Police have been searching the area around Topaz Mountain, a popular rock-hounding spot in remote central Utah, since Monday. Cadaver dogs led police to the site Wednesday just off a dirt road near the mountain's base. The area is more than 130 miles from the location where Powell was last seen at her West Valley City home on Dec. 7, 2009.
The spot is about 30 miles south of where Powell's husband, Josh Powell, told police he took his two sons camping on the night his wife vanished. He told police he and their sons — then 4 and 2 — left his wife at home about 12:30 a.m. The 4-year-old confirmed the trip to police.
Josh Powell is the only person of interest in the case, although he has never been arrested or charged. He has denied having anything to do with her disappearance and said he believes his wife ran off with another man.
On Saturday, the forensics supervisor for the West Valley police arrived on the scene, KSL reported. The station said the supervisor has a degree in anthropology but had been unable to join the search until Saturday.
KSL said that the hole that is being excavated was about 2 feet wide and 3 feet long, and about 2 1/2 feet deep as of Saturday morning.
Susan Powell was 28 when she was reported missing after she failed to show up for her stockbroker job.
Susan Powell's father, Chuck Cox, was escorted to the scene Friday for a look at the excavation effort.
He believes the area amid central Utah's sagebrush-dotted high desert and jagged mountains is a logical place to conduct the search because Josh Powell had camped at nearby Simpson Springs.
Cox, a former investigator for the Federal Aviation Administration, said he had long believed the search for his daughter would be a lengthy process.
"There's no real false hope, it's just another step in the investigation," Cox said. "Every day is hard for the family. Life goes on, and so you go on the best you can. It's something you have to live with."
Msnbc.com staff contributed to this report from The Associated Press.