An autopsy Monday confirmed that the body found in the Yellowstone River on Saturday is that of 15-year-old Utah resident Robert Anthony Thompson.
The youth was visiting Billings last Monday with his mother and 13-year-old sister. They had intended to meet their stepfather, a long-haul trucker who would be passing through.
The family arrived too early to check into the campground and slept in their vehicle near the Dick Johnston Bridge. Sometime during the night, the boy walked barefoot to the river and disappeared.
Boaters on the river found his body Saturday.
“The autopsy did not reveal any signs of trauma indicating foul play, and the cause of death is drowning,” Yellowstone County Sheriff Mike Linder said in a statement. “There is no information to determine why or how Thompson ended up in the river.”