Kyle was reportedly helping another Seal who was suffering from post-traumatic stress disorder when the incident occurred. He was one of two people fatally shot in the incident.
Kyle was shot point blank by the soldier he was trying to help.
Officials said the second shooting victim was a neighbor of the suspect. All three men lived in Midlothian, Texas. American Sniper, which details Kyle's 150-plus kills of insurgents from 1999 to 2009, was published in 2012. The book's cover referred to Kyle as "the most lethal sniper in U.S. military history."