Kyle was honorably discharged from the U.S. Navy in 2009 and published his bestselling autobiography, American Sniper, in 2012. An eponymous film adaptation of Kyle's book, directed by Clint Eastwood, was released two years later.  On February 2, 2013, Kyle was shot dead at a shooting range near Chalk Mountain, Texas. His friend, Chad Littlefield, age 35, was also killed.[10] The former Marine accused of killing Kyle, Eddie Ray Routh, was found guilty of murder and sentenced to life in prison without parole.[