Elmore County Sheriff's Office deputies responded to a report at about 2:30 p.m. of a possible drowning near the Highway 51 bridge.
Upon arrival, deputies learned that an eight-year-old boy had fallen into the river while fishing with his father and uncle.
The boy's father, Jose Jorge Barroso-Alfaro, 37, and his uncle, Martin Barroso-Alfaro, 35, both jumped into the river to try and save the child. A bystander, Michael Feldmeier, 23, of Mountain Home, also entered the river and was able to rescue the boy, but both the father and uncle were swept away by the current.
Witnesses said that both men disappeared under the surface before anyone could reach them.
An Elmore County marine deputy was dispatched to the scene. A marine unit from the Owyhee County Sheriff's Office and the Ada County Sheriff's Office Dive Team were also dispatched.
The Ada County Dive Team conducted an underwater search of the area while Elmore and Owyhee County units searched the banks. Both men were located by the Ada County Dive Team.
Neither man was able to be resuscitated and both were pronounced dead at the scene.
The men were identified as Jose Jorge Barroso-Alfaro, 37, and Martin Barroso-Alfaro, 35. Both men were from Mountain Home.