A tornado touches down near El Reno, Okla., Friday, May 31, 2013, causing damage to structures and injuring travelers on Interstate 40.
Three veteran storm chasers were among the 10 people killed when a violent tornado barreled into the Oklahoma City metro area.
Jim Samaras said Sunday that his brother Tim Samaras was killed. Tim Samaras' son, Paul Samaras, and another chaser, Carl Young, also died.
The men were from Colorado but traveled the Great Plains in search of bad weather.
The three died Friday night near El Reno when an EF3 tornado with winds up to 165 mph hit the Oklahoma City area during rush hour.
The national Storm Prediction Center in Norman, Okla., said the men were involved in tornado research.