Porcupine River

Relying on genetic testing and genealogy research, state troopers in Alaska confirmed that a skull found by the Porcupine River in 1997 was that of Mr. Sotherden.

In 1976, Gary Frank Sotherden’s appetite for adventure and the outdoors led him to the Arctic Circle, where he and a friend planned to walk on opposite sides of the Porcupine River in northeastern Alaska, reuniting when the cold set in and the river froze, his brother said.

Their parents hired a mountain guide, who searched for Gary Sotherden by canoeing up the Porcupine River in 1977.

In July 1997, a hunter found the skull along the Porcupine River — about eight miles from the Canadian border, near where Mr. Sotherden went missing — and turned it over to the police, the troopers said.

OLD CROW, Yukon — Perched on the edge of the Porcupine river, Dana Tizya-Tramm pointed upstream to a stand of black spruce trees that jutted into the partially-frozen water.