A Texas jury found ex-Marine Eddie Ray Routh guilty of murdering Chris Kyle (pictured above), the man who inspired the Oscar-nominated film "American Sniper" and his friend Chad Littlefield, dismissing the defense's assertion that Routh was not guilty by reason of insanity.

The verdict came down late on Tuesday after about two hours of deliberations and Eddie Ray Routh was sentence to life in prison. Routh, 27, admitted to the murders of the famed Navy SEAL, known as the most lethal sniper in U.S. military history, and Littlefield, but pleaded not guilty. A defense witness testified that Routh suffered from schizophrenia and was in a psychotic state at the time of the murders.

On February 2, 2013, Kyle and Littlefield took Routh, another former soldier who had deployed to Iraq and Haiti, to a shooting rage at the behest of his mother, who asked Kyle to help her son cope with post-traumatic stress disorder (PTSD). Routh shot both of them from behind at the range.

He then stole Kyle's pickup truck and purchased tacos at a drive-through window and ran assorted errands, which the defense categorized as clearly delusional behavior. The prosecution countered that the way Routh waited for Kyle to empty his gun, and the subsequent high-speed chase he led police officers on indicated that he "knew it was wrong."

According to the Dallas Morning News, at one point on Tuesday defense attorney R. Shay Isham mentioned that Routh's mother was asked repeatedly why she didn't tell Kyle about the extent of Routh's mental illness, causing Kyle's widow to storm out of the courtroom.

The prosecution consistently painted Routh as a troubled drug user who knew right from wrong, despite any mental illnesses. While trial testimony and evidence often included Routh making odd statements and referring to insanity, he also confessed several times, apologized for the crimes and tried to evade police.

es/bw (AP, Reuters)