PAVILLION - As the digging continued Tuesday, an official with the Fremont County Sheriff's Department confirmed that authorities are looking for human remains behind a house eight miles east of here.

Anthropology students, under the guidance of professor Rick Weatherman from the University of Wyoming, sifted through sand and soil in the sage desert under unrelenting sunshine, hoping to uncover evidence that will help solve a 28-year-old missing persons case.

Virginia Uden and her sons, Reagan and Richard Uden, disappeared Sept. 12, 1980, and were never found.

Virginia's mother, Claire Martin, was the last person to see her and the two boys when they left Martin's house in Riverton to meet Uden's ex-husband, Gerald Lee Uden, in Pavillion.

The Wyoming Division of Criminal Investigation recently uncovered new information which prompted the excavation, sheriff's officials said.

Officials and students began the dig on Monday afternoon at a home just north of Ocean Lake which was once owned by Gerald Uden and his wife, Alice, whom he married after divorcing Virginia.

Gerald bought the house and land and a connecting parcel in two transactions in 1977 and 1978, and sold the properties in 1985, according to Fremont County records.

The residence has changed hands a few times since, and the current owners, who purchased it less than a year ago, have nothing to do with the investigation.

The Star-Tribune unsuccessfully attempted to contact Gerald Uden on Tuesday.

Detective Sgt. Bill Braddock with the sheriff's department said the painstaking process of excavating and looking for potentially decades-old remains could go on for days, and investigators might not know if they've found anything until they get results from the laboratory.

"We're going to do a square-by-square search," Braddock said Tuesday. "The students are working with a lot of enthusiasm, but it's a slow process, and it's going to take some time."

The current owners of the property have been "very gracious" to give county and state authorities access to the land, he said.

Gene Wyant, who has lived near Gerald Uden's former home since 1978, observed the operation from the road near the dig site Tuesday. Wyant hopes authorities will solve the mystery about what happened to Virginia and her boys, so Virginia's family can finally have some closure after all these years, he said.

Wyant knew Gerald Uden when he was a neighbor; and his daughter was a pen pal with Uden's daughter. But he's as much in the dark as everybody else seems to be regarding the mysterious disappearance, he said.

During the sifting process Monday and Tuesday, investigators possibly found some items of interest, Braddock said. But they will need to be lab-tested before authorities know anything for certain.

Authorities are not digging in or around any concrete pads, Braddock said, nor do they plan to, contrary to rumors that have emerged on the Internet, and among locals who have followed the case closely for years.

When Virginia Uden went missing in September 1980, she was just about to turn 33. She told her mother Gerald Uden was going to take sons Richard, 11, and Reagan, 10, bird hunting.

The 1973 Ford station wagon which Virginia had been driving, and which she'd borrowed from her mother, wasn't found until almost a month later. It was in the isolated Dickinson Park area of the Wind River Mountains on the edge of Trout Creek Canyon, about 20 miles west of Lander and about 35 miles southwest of the dig site.

Large amounts of blood matching Virginia's blood type were found in the rear, middle and front of the car, and somebody had apparently tried to push the car off the embankment, out of sight into the bottom of the canyon. But when the car became lodged just 75 feet from the top of the embankment, somebody then tried to hide the vehicle under pine boughs cut from nearby trees.

State and local authorities have long suspected that Virginia, at least, was murdered, but despite years of searching, and on-again, off-again investigations, police have failed to gather enough evidence to arrest or prosecute any suspects.

Reporter Chris Merrill can be reached at chris.merrill@trib.com or at (307) 267-6722.