Steven Bevelhymer has been missing in the Missouri near Ponca State Park since the weekend.
Crews are now using sonar to try and find a man missing in the Missouri River near Ponca State Park in northeast Nebraska.
The Nebraska Games and Parks Commission says 55-year-old Steven Bevelhymer and 49-year-old James Bevelhymer, both of Ponca, fell overboard on Saturday while trying to anchor the fishing boat.
James Bevelhymer climbed back into the boat and called for help. He was treated for hypothermia. Steven Bevelhymer remains missing.
Commission spokesman Jerry Kane says he doesn't know if the two men are related.
Dive operations were temporarily suspended on Monday because of difficult and unsafe conditions on the river.