Could defendant's appearance impact "American Sniper" trial?

As the high-profile "American Sniper" murder trial begins Wednesday with opening statements, accused killer Eddie Routh's drastic change in appearance is garnering attention. It's a change that may not work in the former Marine and Iraq veteran's favor as he tries to plead insanity, according to a legal expert.

"If you see what he looked like at the time of his arrest, he really looks crazy. I mean, he looks like someone who has really had difficulties," CBS News legal analyst Rikki Klieman said Tuesday on "CBS This Morning."

Now, Klieman said he does not "in any way" look like the same person.

"What he looks like today is a reasonable person. He looks like someone who has put on a fair amount of weight; he has the glasses; he's communicating with his lawyers," Klieman said.

That could be bad news for the defense.

"His appearance back then at the time of the crime was of someone who really had a problem," Klieman said.

Routh allegedly shot Navy SEAL Chris Kyle, whose life was the subject of Oscar-nominated blockbuster "American Sniper," and his friend Chad Littlefield at a gun range on Feb. 2, 2013.

Prosecutors are not seeking the death penalty for Routh, which Klieman said is a great strategic move.

"The prosecution, if it went to seek the death penalty in this case, would have the problem that ultimately that the jury would know that he does suffer from post-traumatic stress disorder," Klieman said. "The prosecution has taken that mitigating factor out. It's a smart, smart move."

The jury is made up of 10 women and two men, with one man and another woman selected as alternatives. Klieman said the number of women on the jury is "a bit startling."

"We can only deal in stereotypes here, and we understand that we don't know enough about these 10 women. However, you have to believe that in a quick jury selection like this, that there was a thought on the part of the defense that women would be more sympathetic, more empathetic, toward an insanity defense that is being put forth here," Klieman said. "So I get the defense."

As for the prosecution?

"Well, it's very possible that the prosecution said maybe women are more empathetic and sympathetic and they are going to feel for this great American hero, Chris Kyle. While saying that, I could not possibly be more stereotypical and more sexist by those comments," Klieman said.