Army Corps of Engineers and tribal officials searched the banks of the Snake River on Friday for any ancient artifacts or bones following Sunday's discovery of some apparent skull fragments.
Nothing new was found.
Now the Corps will consult with regional tribes and a physical anthropologist to determine the age of the bones discovered in the muddy river bed upstream of Ice Harbor Dam.
Findings from any examination likely won't be available for weeks, said officials.
Rodrigo Negrete was spending time with friends fishing in the river Sunday when he decided to take a break and search for clams instead.
Walking in the mud, the Kennewick man said he felt a rounded object beneath his foot and reached into the muck to pull out what he thought was a very big clam.
When he lifted it up and showed it to his friends, they thought he'd found part of a turtle shell. But he thought otherwise.
"I washed it off and thought it could be a skull," Negrete told the Herald.
The fragment appeared to be the top of a skull with a portion of the eyebrow ridge and nose. It broke into two pieces as he pulled it from the water.
Negrete said he wasn't convinced it was a human bone so he left the pieces on the riverbank.
But when he got home and told his wife, Blanca, she wanted him to call the sheriff's department.
"I told him that could be someone's daughter," she said.
He returned to the site the next day, found the fragments and met with a Walla Walla County Sheriff's deputy at the fire station in Burbank. Later, he took officials to where he found the remains.
The Corps has jurisdiction over the portion of the river where the bones were found. And a preliminary examination shows it is likely from a Native American burial, said Corps spokesman Bruce Henrickson. "We treat them with appropriate respect," he said.
In addition to consulting with an anthropologist from the Pacific Northwest, the agency will work with the Columbia Plateau Inter-Tribal Repatriation Group. The group includes the Confederated Tribes of the Umatilla Indian Reservation, Yakama Nation, Confederated Tribes of the Colville Reservation, Nez Perce and the Wanapum Band.
Chuck Sams, a Umatilla spokesman, said discoveries of Native American remains happen every year in the region. Societies tend to congregate along waterways to form settlements so it isn't surprising that something could be found by someone, he said. They could belong to one of several tribes based on where they were found.
"It's kind of a convergence (area)," Sams said.
The oldest remains found in the region were the bones of the Kennewick Man skeleton found in Columbia Park during Water Follies in July 1996.
The discovery of the 9,300-year-old skeleton sparked a nationwide controversy between Indian tribes and parts of the scientific community after scientists insisted they needed to study such remains if they are ever to understand the earliest inhabitants of North America.
Henrickson said the Corps does not plan any further searches of the Snake River site.
Federal law protects the remains and burial sites of Native Americans.
However, Henrickson said it's important people report finding possible human remains because while they could be Native American, they also could be from a crime scene.
Blanca Negrete said she hopes the remains can be properly identified and returned and is glad to know they are likely not the result of a crime. If anything, she and her husband has a story to tell.
"I've been fishing for 15-plus years," Rodrigo Negrete said. "We've never found anything weird like that."
-- Ty Beaver: 509-582-1402; firstname.lastname@example.org; Twitter: @_tybeaver