Chris Kyle, a retired Navy SEAL who is recognized as the most lethal sniper in U.S. military history, was shot and killed at a gun range in Texas on Saturday by a fellow former soldier who he was trying to help overcome post-traumatic stress disorder. 

Around 3:30 p.m. on Saturday, the 38-year-old Kyle and another man were allegedly shot and killed at Rough Creek Lodge's shooting range by Eddie Ray Routh, a 25-year-old highly trained Iraq war veteran, the Stephenville Empire-Tribune first reported. The Star-Telegram reports Routh was arrested about five hours later at his home in Lancaster, which is about 70 miles away from the range where Kyle was shot, after a brief chase with police that only ended after police deployed spike strips to stop Routh from fleeing. The local NBC affiliate reports Routh was arrested driving Kyle's Ford pickup truck, but that was not confirmed by authorities.

What happened at the shooting range, and why, remains unclear. Police said there's no apparent motive right now. NBC 5 reports the other man killed was 35-year-old Chad Littlefield. Other reports indicate he was also a veteran and possibly Kyle's neighbor. WFAA reports that sometime between 3:30 p.m. and 4 p.m. Routh turned and shot the two men at point-blank range; and that Routh was working with Kyle to overcome his post-traumatic stress disorder. Kyle helped found the FITCO Cares Foundation to help other veterans overcome the disease.  

Kyle is often credited as the most lethal sniper in U.S. military history. He served in four tours of duty in Iraq until his retirement in 2008. His exact number of kills is unknown (the confirmed number is 160) but some reports have put the number closer to 250. In all, he was awarded two Silver Stars, five Bronze Stars with Valor and two Navy and Marine Corps Achievement Medals for his service. 

His book, American Sniper, was a New York Times best-seller. There were reports it was going to be made into a movie, with Bradley Cooper set to star as Kyle. This is an interview Kyle did with Conan O'Brien last February to promote the book: