A fluke discovery of children's bones protruding from a badger hole in southwestern Idaho has investigators trying to determine if they have discovered a double homicide or the disturbed grave of young 19th century pioneers who died going west on the nearby Oregon Trail, authorities said Tuesday.
Authorities thought one body was at the site in high desert sagebrush steppe discovered by state fish and game workers who stumbled across the bones while out on a routine patrol.
But a forensic anthropologist determined that the remains are of a child between ages 4 and 6 and a teenager or young adult between the ages of 16 and 20.
Carbon dating results expected in several weeks should help determine when they died, said Greg Berry, the undersheriff of Elmore County.
Investigators hope that information will help them conclude whether the site was an unmarked Oregon Trail grave site or a possible dumping location for homicide victims.
"It's a mystery, for sure," Berry said.
The Oregon Trail during the 1840s through the 1860s stretched about 2,000 miles (3,220 kilometers) from Independence, Missouri, to Oregon City, Oregon -- crossing Idaho through the Snake River Plain.
Historians estimate that up to 400,000 pioneers attempted it and other trails that branched off it, with death estimates of those heading west ranging from 4 to 10 percent. While pioneers' diaries have reports of children falling and dying under wagon wheels, diphtheria was thought their main cause of death.
So-called "bomb carbon dating" of the bones will determine whether the two lived before or after the introduction of atomic radiation to the atmosphere from atmospheric nuclear bomb tests in the 1950s, said Samantha Blatt, the Boise State University anthropologist examining the bones. Depending on the results, additional tests could narrow the period when the two were living.
Blatt said she has not determined the genders of the two and that "the appearance of the bones suggests that they are not too recent."
"It is certainly possibly these individuals were from the time of the Oregon Trail, but more tests will need to be done to conclude anything for sure," Blatt said.
Investigators have no evidence to suggest how the two died and will decide after the carbon dating whether to pay for additional testing to determine the cause, said Elmore County Sheriff Mike Hollinshead.
A main part of the Oregon Trail lies about 5 miles (8 kilometers) south of the site where the bones were found. Pioneers were known to spread out to the sides of the trail in search of flat areas where their livestock could graze, said Shane Wilson, an archaeologist with the U.S. Bureau of Land Management.
"The Oregon Trail wasn't a single path," he said. "If there's no feed, you're going to go where feed is with your oxen or pulling animals."
Elmore County authorities have asked other Idaho law enforcement agencies to provide information about old cases of missing children.
The fish and game workers on April 15 were checking the licenses of ground squirrel hunters when they found the bones on federally owned land about 5 miles (8 kilometers) from the small city of Mountain Home. There are badgers in the area that also hunt the squirrels.