The former US Marine who killed American Sniper Chris Kyle and his friend Chad Littlefield has been moved into a psychiatric prison for evaluation of whether he should be moved into the general prison population . Eddie Ray Routh was transferred on Monday to Jester IV Unit , a psychiatric facility in Richmond , about 25 miles outside Houston . Routh was convicted on February 28 of double murder and sentenced to life in prison without parole . Scroll down for video . This new picture of Eddie Ray Routh shows him after he was admitted to the Texas prison system following his February 28 conviction for the murders of 'American Sniper ' Chris Kyle and Chad Littlefield . Routh , pictured here during his trial , argued that he was insane and not criminally liable when he killed Kyle and Littlefield in 2013 . His lawyers argued that he suffered from mental illness , including PTSD from his time serving in the military , even though he never saw combat . A jury rejected his insanity defense that he should be put in a psychiatric treatment facility instead of prison . However , because of his psychiatric state , Routh could still be kept out of the general prison population and be kept in a mental facility in the prison system instead . He was transferred from a state prison near Abilene , where he underwent an initial evaluation , to Jester IV Unit , which has more advanced medical facilities . Chris Kyle ( left ) and Chad Littlefield ( right ) were gunned down after taking Routh to a shooting range . When Routh was transferred from county jail into the state prison system on March 6 , a new booking mugshot was released by the Texas Department of Criminal Justice . The Marine veteran appears thinner since he last appeared in public on the day of his murder conviction . The 2013 murder of Kyle , a Navy SEAL who wrote the best-selling book American Sniper , and his friend Littlefield drew nationwide attention . Kyle is the deadliest sniper in American history , with 160 confirmed kills . His trial took place not long after the release of 'American Sniper ' the movie , an Oscar-winning biopic that starred Bradley Cooper as Kyle .
Eddie Ray Routh was transferred to Jester IV Unit , a psychiatric prison in Texas , Richmond . Officials are determining whether he is stable enough to put in the general population .