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STEPHENVILLE, Texas — A Texas jury found a former Marine guilty of murder late Tuesday in the killings of "American Sniper" Chris Kyle and his friend Chad Littlefield.

Eddie Ray Routh showed no reaction as a judge sentenced him to life in prison without parole, an automatic sentence since prosecutors didn't seek the death penalty in the capital murder case. They jury rejected Routh's insanity defense.

As one of his victim's siblings called him an "American disgrace" shortly after, Routh looked back at the man intensely but didn't react otherwise.

"You took the lives of two heroes, men who tried to be a friend to you," Chad Littlefield's half-brother Jerry Richardson told Routh after the verdict.

The jury announced its verdict at around 9:20 p.m. local time (10:20 p.m. ET) courthouse. They were given the case at 6:36 p.m. local time (7:36 p.m. ET).

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"We just want to say that we've waited two years for God to get justice for us on behalf of our son and as always God has proved to be faithful, and we’re so thrilled that we have the verdict that we have tonight," Littlefield's mother, Judy Littlefield, told reporters after the verdict was read.

Routh, 27, admitted to killing both men at the shooting range of Rough Creek Lodge and Resort, southwest of Dallas, on Feb. 2, 2013.

Routh pleaded not guilty by reason of insanity to capital murder. His attorneys have said Routh, a former Marine corporal who served in Iraq but not in a combat role, was in the grip of a medically diagnosed psychosis at the time of the killings.

Kyle's widow, Taya Kyle, was not present when the jury read its verdict. She appeared to get angry and left court as the defense presented its closing statement, NBC Dallas-Fort Worth reported.

Prosecutors said that Routh was drinking and smoking marijuana on the morning of the crime. They argued that he was paranoid because he was high, and that he was angry about living with his parents, relationship problems, money and his job — then exploded after he believed Kyle and Littlefield snubbed him.

Experts for the prosecution have testified that Routh knew what he was doing was wrong when he killed the two men.

Earlier Tuesday, jurors heard a recording in which Routh told a reporter nearly four months after the killings that, "It tore my (expletive) heart out what I did. I don't know why I did it, but I did it."

Routh, speaking to a reporter from The New Yorker magazine on May 31, 2013, also said, “I feel so (expletive) about it. I guess you live and learn, you know."

"American Sniper," the movie based on Kyle's account of his experiences as a Navy SEAL, was nominated for best picture at the Oscars.

Kyle's widow attended the ceremony on Sunday night before flying back to Texas for the rest of the trial.

The Associated Press contributed to this report.