reporter: kristi itzo explained how her normally stoic brother was overcome with profound grief. he was crying, he was curled up in a ball. he grabbed me. we cried for 20 minutes, and all he wanted was debbie back. reporter: but the defense knew their case hinged on one thing lars state of mind the moment he pulled the trigger. i need you to raise your right hand. reporter: and there was only one person who could tell that to the jury. coming up, a grieving husband? or a lying one? the love of your life? yes, sir. the person you know better than anybody else. yes, sir. and you can t tell it s her when you pull that trigger? when dateline continues. n s new emergen-c crystals pop and fizz when you throw them back. and who doesn t love a good throwback? [sfx: video game sound]
sense any marital conflict? no. reporter: kristi itzo explained how her normally stoic brother was overcome with profound grief. he was crying, he was curled up in a ball. he grabbed me. we cried for 20 minutes, and all he wanted was debbie back. reporter: but the defense knew their case hinged on one thing lars state of mind the moment he pulled the trigger.
reporter: just before 10:00 a.m., police let lars go. ken and kristi remember their younger brother that morning, overwhelmed with grief. he was completely hurt shattered, you know. he was broken. in those hours afterwards, what was he talking about? he really wasn t talking. he was just in shock. if he opened his mouth, he broke down. reporter: across town debbie s tennis friends were out on the court, waiting for her to start that early morning match. reporter: one of their husbands came out to tell them about debbie. reporter: in arkansas, jim and anne kelly learned the news from their son. that s just the worst news that a mother could ever hear. how does your brain process that information? i don t think you do. i couldn t process the shooting part, i guess. it was just that she was gone. and a part of me died the day she died. just kept saying, not debbie, not debbie, not deb. reporter: debbie s parents flew to san antonio, to spend time with lars, to su
detective. they re not done when he s alone. what was he doing when officers were not watching him? he sat in this manner, sleeping at moments. reporter: and sipping his signature drink, dr. pepper. free on bail, lars understood he was still under the microscope. it was difficult. he didn t sleep much. reporter: watching lars suffer was torture for ken and kristi. they knew how much their brother loved debbie and how dark and confusing that house could be at night. you felt it was important that we come to the house now. yes, i did. why? because no one realizes how dark it was. we re here. it s around 4:00 in the morning. yes, it is. reporter: this was lars and debbie s bedroom. the bed was on this wall. reporter: ken itzo walked us through the story lars told him countless times he wasn t sure what he was seeing. he just thought it was an intruder, maybe two. there s the thought of, well, debbie s only 5 3 , she s blonde. she was wearing a light t-shirt
she is deceased. dammit. reporter: just before 10:00 a.m., police let lars go. ken and kristi remember their younger brother that morning, overwhelmed with grief. he was completely hurt shattered, you know. he was broken. in those hours afterwards, what was he talking about? he really wasn t talking. he was just in shock. if he opened his mouth, he broke down. reporter: across town debbie s tennis friends were out on the court, waiting for her to start that early morning match. reporter: one of their husbands came out to tell them about debbie. he called me over and said that lars had shot her. what are you thinking when you hear that? out of the box for you. it was very surreal. i couldn t even comprehend how could someone shoot somebody?