The crime uphold the city of Atlanta a father killed outside a preschool. This February high drama at the DeKalb County courthouse as the man who did it faces trial. Attorneys for accused killer... See More
The crime uphold the city of Atlanta a father killed outside a preschool. This February high drama at the DeKalb County courthouse as the man who did it faces trial. Attorneys for accused killer having him and Begin with a stunning admission. On November the eighteenth. 2000 -- -- -- -- -- -- -- -- -- pleads not guilty by reason of insanity. He will have the burden of -- to the jury he did not know right from wrong would pull the trigger. It was madness that drove him to kill his attorneys say. And the woman's. -- -- happens when he felt for him. If you want to let infatuation. If you won't -- that. -- -- fiddle for. Newman tells psychiatrist voices in his head telling him to do evil thing. And I can imagine your reaction when you first heard. His story of the angels and team and this. Who appeared to him we left sounding like Jerry white and -- live in Newton-John. This is ridiculous. That was our reaction this is absolutely. Ridiculous. -- buried white demon urged. Human to kill himself. -- another voice sounding like Olivia Newton-John. -- told him to -- rusty snyderman because rusty was a danger to his two children. So the Angel told him get the children and kill us. But defense doctors say the successful engineer was bipolar. Deranged by delusions. Finally driven -- trying to head over heels infatuation. -- -- -- There's adultery that occurs -- -- huge leap to murder somebody. You have -- who's about to file bankruptcy you have Amy who's unhappy with his wife. He wants a change. The on the problems of the life he wants is being occupied by someone else. His lawyers paint a harrowing picture of pennies childhood. A father who was a survivor of -- woods who physically abused his children and a mother who was largely absent. The prosecutor -- -- tells the jury there is a simpler explanation. And when someone else's life. The sentences and -- lawyers say is -- and Andrea worked and traveled together. She turned his illness and infatuation to her own purposes. You think she meant to get him to kill her yes yes. Absolutely. This is clearly a situation here where where one person was mentally ill. -- and the other person was aware of it and was calculating and was and was manipulative. That other person is -- grieving widow Andrea Snyder night. The star witness in the trial of her husband's killer. And suddenly she is on the defensive. I think than ever express his feelings from. Yes. Andrea says Newman wrote her -- -- And Colin insinuated that she thought I was beautiful do you have any idea why the thing we have instant. Pretty nice person. And caring parents and -- the defendant romantically involved. Prosecutors rattle Andrea with chains of -- businesslike emails from hammy. It's about how would you felt when we look at the sources tell when we woke up Friday morning in Denver and when we walked out of the restaurant on Thursday when you took my hand in essence you have my shoulder and. Do I have. Did you wake up together in Denver. No. Andrea says she rejected numerous advances by hammy but didn't mention them to her husband. -- -- -- -- -- -- I really felt that I could handle it. Penny even emailed a proposal marry me it says think about it be with me forever. Andrea says she can explain. It very much and takes something away -- -- -- -- -- -- -- I spoke to him about that email networks and person he told him -- Andrea admits she cared about -- as a friend she managed to get me to care. That's actually point. This very -- -- very good at. Manipulating everyone around -- few African. Andrea say she allowed -- into her room at hotels when they travel together but says that was before she realized he was stalking her. Didn't stop you from inside you. Stalking can -- -- many different meaning and so that's -- yes he -- Paris entitlement me anyway. Being your. I do not share her with me -- in my group minded and -- allotment -- -- reminds me. When the defense attorneys get their turn to question her they suggested -- was stalking Andrea she made it easy forum that stop -- That you. Now testified about you pick him up at the airport. You flew home -- that's correct you change seats to sit next to him. -- -- -- -- After a trip to Greenville, South Carolina with -- they have a revealing email exchange in which Andrea says I now have to repent. We turn the second page that -- can't finish this please. Never forget how much I loved it and how did you respond. Now some 200 people. Converging on a chance to do it and her. What happened. We were. Holding each other's hands. Friends that's it. It may sound worse than -- -- to me -- me and the trail. You're painting. In the email is. From holdings -- yet. What you think when she took the stand. If I were her lawyer -- flung myself out -- -- How he could have let her go up there and not take effect at night but what qualities did you see it stands today combative. Years. Angry. You know. -- mean it it was at the tone of the whole thing was how the year acute challenge me. I mean the most the most telling quote of the whole thing was him the time periods -- When. He said -- should leave the police or she looks -- -- -- -- -- his -- He's seeing what's happened to -- done boss Hart said -- -- what happened rusty. See what's happened to ask you notice what's happened to my life since he was her sense of humor and -- -- The suggestion of an affair is one thing murder is another. When we come back the courtroom was rocked by revelations about what Andrea knew about her husband's shooting that was a bombshell. That was pops up at that point did they tell you -- indication -- wasn't that. Is that the first time we found out he was yeah and you found out he was shot.
This transcript has been automatically generated and may not be 100% accurate.