A teenage boy is presumed drowned after the boat he was in capsized on the Snake River late Saturday, according to Columbia Basin Dive Rescue.
The boy's name and hometown were not available Sunday.
Dive Rescue was called to the Hood Park boat launch near Burbank just before midnight Saturday.
Four adults and the teen, believed to be 14 years old, had been fishing near the boat launch upstream from the Highway 12 bridge. The adults in the boat made it to shore but not the teen, said Scott Ruppelius, spokesman for Dive Rescue.
No one wore a life jacket, he said.
Dive Rescue searched for several hours early Sunday, then returned during daylight and searched until shortly before 4 p.m. The Walla Walla Sheriff's Office and Coast Guard were on scene through the night.
The Franklin County Sheriff's Office also was on the river, using the SARbot, an underwater search and rescue robot purchased earlier this year after two years of fundraising by Franklin County officials.
At least six boats, including a Washington State Fish and Wildlife boat, were searching the Snake River on Sunday afternoon.
A group of family and friends stood in an area marked off by yellow police tape at the boat launch, watching the search and hugging each other.
The sunken boat was located about 25 yards from the boat launch and divers could be seen entering the water near it Sunday afternoon. It had not been brought to the surface by midafternoon Sunday.
Law enforcement officials were restricting access to part of the Snake River on Sunday, but the Hood Park boat launch remained open and busy.
Dive Rescue volunteers plan to return Tuesday to perform an underwater search, Ruppelius said.