'American Sniper' Widow Taya Kyle Says She Put Hate for Chris Kyle's Killer Behind Her

— -- Taya Kyle, widow of “American Sniper” Chris Kyle, now an advocate for veterans' families, talked about having to face her husband’s murderer Eddie Ray Routh in court, and though forgiveness is still out of reach for her, she said hate is behind her.

“It's okay not to understand all the reasons why. But to see how you can be better for it and what you can take away from it, how you can help others, because we all have something,” Taya Kyle told ABC News' Robin Roberts in an exclusive interview. Watch the full interview, "Love. War. Renewal. The Taya Kyle Story," on a special edition of ABC News' "20/20" HERE.

“That's why God tells us not to hate, because the moments where I had just disdain, disgust, like any focus on that person, it hurt me,” she added.

In the wake of her husband's death, Taya Kyle has written her own book, "American Wife: A Memoir of Love, War, Faith and Renewal," which details their love story, how she and her family dealt with his death, and her life as a military spouse. The book will be released on Monday, May 4, in collaboration with Jim DeFelice and published by William Morrow Publishers.

Nearly three years after coming home from Iraq for good, Chris Kyle became a bestselling author with “American Sniper,” also co-written with DeFelice, which chronicled his war experience. He also began helping fellow veterans adjust to civilian life by taking them to a Texas hunting resort, Rough Creek Lodge. He found that hunting and target shooting helped veterans relax and open up.On Feb. 2, 2013, Chris Kyle was doing just that with Routh, a Marine who graduated from the same high school a decade after Chris Kyle. Routh had served as a Marine in Iraq and was a rescue worker in Haiti after the deadly earthquakes.

Routh’s mother reached out to Chris Kyle for help with her son, who, after he returned home, was acting erratically, smoking marijuana, drinking heavily and even threatening suicide. Though he had never met Routh, Chris Kyle agreed and asked his friend Chad Littlefield to come with him and Routh to Rough Creek Lodge.

After waiting for Kyle to fire all his shots down range, Routh used one of Kyle’s 9 mm handguns to shoot Littlefield six times, killing him. Routh then killed Kyle with six shots.

“Neither one of 'em saw it coming,” said Taya Kyle.

Routh, who pleaded not guilty by reason of insanity, was convicted of capital murder in February 2015. He received an automatic life sentence without the possibility of parole.

Taya Kyle was a constant presence at the widely publicized trial, and testified for the prosecution.

“There’s a consequence for everything, and that goes back to the Bible for me,” Taya Kyle said of the verdict. “You can forgive somebody and still believe they need a consequence.”

Taya Kyle said being in the courtroom mere feet away from the man who murdered her husband brought on a wave of different emotions for her.

“When it was autopsy type pictures and [Routh] would be staring at them, I wanted to come out of my seat, like, ‘Don’t you dare look at them in that vulnerable state, you don’t have the right,’” Taya Kyle said.

As part of his defense, Routh’s lawyers told the court that Routh didn’t understand that it was wrong to kill. The defense called family members, friends and psychiatrist Dr. Mitchell Dunn, who testified that Routh had serious mental-health issues before murdering Chris Kyle and Chad Littlefield. Dunn also said that Routh was schizophrenic with delusions that his co-workers were cannibals who wanted to eat him.

But forensic psychologist Randall Price, who the prosecution called as a rebuttal witness among other forensic experts, testified that Routh knew that what he was doing was wrong and was faking schizophrenia.

Prior to his conviction, Routh had spent time in and out of mental hospitals. Routh’s lawyers said during the trial that Veterans Affairs doctors should not have released him. But Taya Kyle doesn't believe mental illness or post-traumatic stress disorder excuses his actions.

“In this situation, though, you know, this guy manipulated, every time he got in trouble, he used some sort of excuse,” she said. “PTSD doesn’t cause you to murder people.”

Though she is still finding her way in a life without her husband, Taya Kyle said she is moving forward.

“I think everybody goes through things in their life where they're like, ‘This does not make any sense,’ or ‘I don't understand why this is happening,’ but that's part of the journey of faith,” she said.