Chris Kyle killer Eddie Ray Routh found guilty of murder and sentenced to life in prison

Unanimous verdict came after just two hours' deliberation by the jury

Eddie Ray Routh had pled insanity over the deaths of Chris Kyle and Chad Littlefield (EPA)

After deliberations in a courthouse in Stephenville, Texas, that lasted barely two hours, a jury of ten women and two men found Eddie Ray Routh, a mentally disturbed former US Marine, guilty of capital murder in the death of Chris Kyle, known as the American Sniper, and a friend just over two years ago.

In the end, the jury returned to deliver its verdict shortly after 9 pm. The jury note was passed instantly to Judge Cashon who, with little pause, said that Routh had been found guilty of capital murder and that he was imposing the only sentence that was open to the court, life imprisonment without parole.

In an odd quirk of court procedure, Judge Cashon then heard so-called victim impact statements from family members of both Mr Kyle and his friend who also died at the hands of Routh, Chad Littlefield. Since the sentence had already been delivered, the statements in the end meant little beyond offering some form of catharsis to those who spoke, including Mr Kyle’s widow, Taya Kyle.

Eddie Ray Routh as a Marine and after his arrest (AP)

“You took the lives of two heroes, men that tried to be a friend to you. You became an American disgrace,” Mr Littlefield’s brother-in-law, Jerry Richardson, said of Routh.

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From the start, the defence was struggling against the extraordinary notoriety of the case and the inevitable influence that that was going to have on members of the jury, however carefully they were vetted and chosen. The book written by Mr Kyle about his four deployments to Iraq where his kill tally topped 160 or more – a record – called American Sniper remains on the best sellers list.

More pervasive than the book in the public imagination, however, is the film of his story, also called American Sniper, directed by Clint Eastwood and starring Bradley Cooper as Mr Kyle which, since its release in January, has become one of the biggest grossing films of all time and certainly the biggest grossing war film. It won one Oscar last Sunday night.

Bradley Cooper as Chris Kyle in blockbuster American Sniper (AP)

The defence had argued to the jury that Routh, who had a recorded history of mental instability as well as drug and alcohol abuse when he was discharged from the Marines after deployments to both Iraq and later to Haiti after its earthquake, was suffering from momentary insanity on a February afternoon two years ago when he shot the victims on a shooting range on a private resort near Stephenville.

It was in the end not an argument that the jury bought and the brevity of their deliberations last night suggested that it probably never had much traction with them. "That is not insanity. That is just cold, calculated capital murder," prosecutor Jane Starnes said in her closing argument. "He (Kyle) absolutely never saw this coming," said crime scene analyst Howard Ryan.

The jurors had heard emotional testimony during the trial, including from Taya Kyle, about how the two men had agreed to take Routh, whom they barely knew, to the shooting range at the Rough Creek Lodge, as a favour because they knew from his family that he was having traveling fitting back into civilian life and could benefit from afternoon letting off steam.