Transcript for Court Overrules Mom's Conviction for Murder of Foster Son
Once again, juju Chang. Reporter: In the six years "20/20" has covered Hannah's case, the mother of five has remained steadfast in her faith and confident her conviction would be overturned. Never during our visits with Hannah, has there been anger or resentment, not even toward the woman who helped put her behind bars -- Sandra Eastwood. I don't know what her intentions were. You know, what her motive was behind it. But I've chosen to forgive her because I can't hold onto that bitterness. Reporter: Hannah's appeal for freedom -- led by defense attorney, Cynthia Orr -- hit several roadblocks before finally winning a new hearing in 2012. At the center of the appeal? Those two doctors who spoke to "20/20" and believe that Hannah is innocent. Dr. Edgar Cortes, finally on that witness stand, insisting he told his concerns about Andrew's health to the prosecutor. I felt like the prosecution had its own theory about what happened. And did you fit that theory? I'm the one that felt that he had other kinds of neurological problems. Reporter: Cortes says his suspicions are backed by this report, an evaluation of Andrew burd by child development specialists back in 2005 before he went to live with Hannah. Do these developmental delays make him mentally younger? Yes. Make him in danger of accidentally harming himself by eating bad things? Yes. Reporter: Also finally getting a chance to testify, Dr. Michael Moritz, that salt poisoning expert, telling the court exactly what he told "20/20" six years ago. The most likely scenario was that Andrew ingested the salt all on his own. And what about the prosecution's argument that Andrew died because they didn't call 911? Moritz says, even if they had, there was little anyone could do to save Andrew. Do you have an opinion, whether or not there was any delay by Hannah or her husband that caused any harm to Andrew? My opinion is no. Reporter: Do you think Hannah Overton knew her child was dying? No, I don't believe she did. I think most people would never suspect salt poisoning since it's something very few pediatricians or emergency rooms in the country have ever encountered. Reporter: In fact, it took more than an hour once Andrew burd arrived at the hospital for doctors to determine he had salt poisoning. Before they figured it out, medical staff actually added fluids containing sodium in an effort to revive him. If she'd called 911 and the ambulance had come as quickly as they could, do you have any opinion as to whether it is more likely than not he still would have died? I would say it would be exceedingly unlikely for him to live. Even with today's medical technology under the best medical care, under major medical centers, and even when it happens in the hospital, you die. Reporter:tzf Mori had told the court his opinion, would the jury still believe Hannah knew Andrew was dying and could have saved him? The defense team zeroed in on the once confident prosecutor. This time around, she seemed nervous. Having difficulty recalling some of the details from the trial. I can not remember. I don't recall. I don't know. I do not remember. Reporter: But Hannah's attorneys didn't buy Eastwood's "I don't recall" defense. Instead, they offer their own theory for her foggy memory, confronting her about aspects of her private life. Do you recall that at the time of this trial, Ms. Overton's trial, that you were abusing prescription diet pills? Your honor, may we approach? I am furious. Just a minute. Don't yell in my courtroom. Reporter: Eastwood is later given the chance to clarify. I said that I was taking prescription diet pills, and I never said I abused that. And then I also stated that in the evening I would drink wine because I was very stressed. Do you consider yourself to have any kind of alcohol or drug problem, Ms. Eastwood? Yes. I believe that I am an alcoholic. And my sobriety date is January 20th of 2011. Reporter: Now remember, Hannah's original trial was back in 2008, three years before Eastwood's sobriety date. Hannah's defense team believes the former prosecutor's drinking influenced her conduct. Eastwood says no way. Do you feel that your use of alcohol or drugs in any way compromised your ability to understand your role as a prosecutor and fulfill those duties during this trial? No. Reporter: Eastwood wasn't the only lawyer in the spotlight. Hannah's original defense team admitted they made serious errors, even breaking down in tears for failing to call the salt poisoning expert. There's probably not a day since this verdict that I haven't -- that I don't regret trying to spend more time on this case to do more. Reporter: But the judge wasn't swayed and denied the appeal. Then, just this past September, the moment Hannah and her supporters had been praying for for years, the state's highest criminal court overruled the judge and reversed Hannah's conviction, putting the blame on Hannah's trial attorneys, not the prosecutor. Just a week after the decision came down, we visited Hannah once again at her Texas prison. It's hard to believe it's true. Reporter: What went through your mind? I said, "Is this real?" And I started tearing up. And then I was like, "Okay, it does say what I think it says." Reporter: What are your plans for the first, you know, taste of freedom that you get? I just want to hug my kids. That's -- that's as far as my plans have gotten. Reporter: You haven't been allowed to do that for seven years. Yeah. Reporter: What do you want to do with them? I mean, just day-to-day things. Just being mom. Cooking dinner, watching TV, whatever. All those things that I've missed out on. Reporter: She has missed so much. The baby girl born just prior to Hannah's trial is now a headstrong seven year old with her mother's dark curls. Their oldest son, the boy in those evidence videos used against Hannah at trial, is now a teenager. How do you catch up on seven years? I don't know. I don't know if you can. I mean, I know we'll make up for it, but I don't know that we'll be able to catch up for seven years. It's gone. Reporter: When we come back, the Overton children have all been doing some growing up. You've stepped up a little bit of a parent around here -- haven't you? Yeah, I've definitely had more responsibilities than most teenagers. Reporter: And the reunion, just in time for Christmas. That's next. (Humming)
This transcript has been automatically generated and may not be 100% accurate.