Prosecutors plan to call the widow of Chris Kyle, a former Navy SEAL and author of the book "American Sniper", to testify when the murder trial of his alleged killer opens Wednesday.

Eddie Ray Routh, a former Marine, is accused of capital murder after shooting Kyle and his friend Chad Littlefield at a gun range in 2013. The defense team is hoping to convince a jury that Routh was insane when he killed both men. His family members say he suffers from post-traumatic stress disorder.

Prosecutors aim to paint a much darker picture. They describe Routh in recent court filings as a heavy drinker and marijuana user with a history of killing animals and threatening women with knives. While the judge has not decided how much of that information can be shared with the jury, prosecutors have lined up what promises to be an emotional first day of testimony when they call Kyle's widow Taya to the stand.

The case has received added attention due to the success of the Oscar-nominated film based on Kyle's book. "American Sniper" with Bradley Cooper playing Kyle and Sienna Miller in the role of his wife, has grossed nearly $300 million.

The scrutiny on the case prompted Routh's lawyers to ask for a change of venue, saying they believed that Routh couldn't get a fair trial due to local prejudice. But District Judge Jason Cashon denied the change of venue, noting that the jury was seated with no more than two dozen people dismissed because of pretrial publicity. And when potential jurors were asked Monday to raise their hands if they would have a problem setting aside what they'd heard and only factoring in what was said at trial, no hands went up.

The case has also brought renewed focus to the mental struggles former military members face. Routh was a small arms technician who served in Iraq and was deployed to earthquake-ravaged Haiti before leaving the Marines in 2010. Authorities say that after the February 2013 shooting of Kyle and Littlefield, Routh drove to his sister's house in Kyle's truck, admitted to the killings and told his sister "people were sucking his soul."

Routh has been in court since the jury screenings began last week, listening to the proceedings.

Another of the first witnesses prosecutors plan to call is Littlefield's mother, Judy. Cashon ruled that she and Taya Kyle can stay in court to watch after testifying.

The state's filings say Routh smoked marijuana, drank excessively and had a history of killing small animals. They also say on Jan. 19, 2013, he threatened his girlfriend and her roommate with a kitchen knife and sword. He was taken to a mental hospital.

On the day of the killings, Routh had been drinking and smoking marijuana and again threatened his girlfriend with a knife, according to a legal filing. After his arrest, he allegedly threatened officers and caused problems while jailed, including flooding his cell.

In response to the attention the case drew, county officials had summoned more than four times as many potential jurors as they would for a regular trial -- not unusual for a high-profile case.

The potential jury field was narrowed over two days last week, when would-be jurors filled out a questionnaire that included inquiries on whether they had seen the movie or read the book, served in the military, had a familiarity with firearms, or ever been treated for a mental condition.

The Associated Press contributed to this report.