Transcript for Laci Peterson's mom remembers the last time she saw her alive
--Captions by VITAC-- 26-year-old Laci Peterson. Eight months pregnant. Vainishing for the day. He married America's sweetheart. They're just perfect together. Why would a beautiful pregnant wife suddenly go missing? This was a legitimate, big Nati national -- There was no leads. Your pregnant wife missing. And Scott is cool as cucumber. Laci's family didn't suspect him. Were there any sign of trouble in the marriage? Hey, beautiful, I'll see you in a bit. Wonder if he's been truthful about everything else. Was there someone else? Scott told me he wasn't married. We did have a romantic relationship. Did you have any idea that your son was seeing another woman? Men have affairs. When their wives are eight months pregnant -- Scott Peterson no longer wanted to be in a marriage. He wanted to B free. Did you murder your wife? You wake up from most nightmares and they're over. Mine was different. I was awake when it started and I've barely slept since. It was December 24th, 2002, a date when life as I'd always known it, stopped forever. One to dispatch. Hi, can I help you? Yes, um, my daughter has been missing since this morning. She's eight months pregnant, she took her dog for a walk in the park. The dog came home with just the leash on. What is your name? My name is Ron. I'm her stepdad. Her husband Scott Peterson is on his way over to the park to try to -- What is your stepdaughter's name? Laci Peterson. The story of Laci Peterson's disappearance made news soon after she disappeared, right? Because it's Christmas eve 2002, and it became national news pretty quickly. A drachcalifornia man is waiting to hear about the disappearance of his wife. Laci Denise Peterson is a 26-year-old female. She's eight months pregnant. She's considered a high-risk missing person under suspicious circumstances. I love my daughter. So much. I miss her every minute of every day. I started reporting on it right away, when she was a missing person, the day after Christmas. I think what caught everybody's imagination was Laci Peterson, and her picture. People saw this photo of this missing woman with the big smile and the brunette hair, 8 1/2 months pregnant. Laci was last seen by her husband Scott, when she was walking a dog, possibly in the area of east la Loma park dry creek. He saw her at 9:30 in the morning before he went fishing, and shortly thereafter, she went on her walk. No one has seen her since. Please bring her back to us. Please. The community mobilized immediately, as soon as Laci disappeared. People were helping to search for her. When I got there I was, I was pretty shocked. They already had people making fliers. I mean, they were going door to door. They were in the park. Laci went missing Christmas eve. She's 27 years old and she is over eight months pregnant. This entire factual scenario read like a, like a breathtaking novel. You have an incredibly beautiful attractive couple. Scott Peterson was this good looking, kind, young husband who was about to have a baby and that's a guy a lot of people can relate to. She is carrying their first child. She's just weeks out from birth. I mean, at this point, the baby Connor is viable. Had she given birth within days of her disappearancehe would have lived. Scott and Laci Peterson, I mean, it's right out of a romance novel. They were both at school together. And they met and she fell head over heels in love. And that was it. They were college sweethearts. Laci was very headstrong. She was born in may. She was a taurus and she fit the description to a "T." She was very headstrong. And like I said, once she made up her mind, she was going to do it, and that's all there was to it. There was no changing her mind. Describe your son for me. Describe Scott Peterson. Gosh, where should I start? He was a -- he loved to hug and kiss and, very affectionate. Just -- just a really kind, you know, sweet little guy. Never in trouble of any kind. He was too good to believe, almost. She saw him at the little cafe that he worked at, in morro bay, and before she left that evening she had written her phone number down on a piece of paper and given it to the other server to give to Scott, and when he gave it to Scott, Scott just looked at it and threw it in the garbage because he thought it was kind of a joke until she came back. As I said, she wasn't intimidated by anything. How did you know you were in love? Driving along the highway, uh, I remember vividly. On highway one. And for no reason I was just smiling. Just the biggest smile. And she asked me what -- what the heck are you smiling about? And the only thing was that she was there. When I met him, I was impressed. He was very likeable. He was a gentleman. He was a very nice person. He had roses on the table, a dozen roses for Laci, and then he had some roses for me, so of course that impressed me. I thought well, a very nice gentleman. They were just starting out. They had been married not very long. They had bought the house a couple of years earlier. Laci was a, a homemaker. I mean she loved to cook and her home was -- and she was fastidious. She had taken great pains to decorate it. It was small, but lovely on the inside. They opened a restaurant together, a little burger place. You see the photos of them, all smiles. Laci, by all accounts, was just a bundle of energy, and was always concerned about helping other people. He was a fertilizer salesman. He had a decent job. He's in the wine club. Belongs to the country club. He wants to be that rich guy with that trophy wife. He was still in his 20s. He was about to turn 30. How did Scott feel about the fact that he was going to be a father? Very excited. Happy. He built a nursery? Yes, mm-hmm. Called us at 7:00 in the morning when she took the test. And I said, how do you know? And she said I took the test. I said, those aren't always accurate, you know? And she said, yes it is, yes it is, because she -- they had been -- they tried for three years to have a child. Mm-hmm. Yes. I remember the last time I saw Laci. She and I were sitting side-by-side and Scott was sitting in the floor, and we were watching TV and she said the baby was kicking, so I put my hand on her stomach, because I'd never felt him kick. She leaned over to me and she said mom, she said Scott doesn't like to do this. She said I've asked him about, you know, feel my stomach when um, when the baby kicks and he never wants to touch my stomach. That really, really bothered me, and that was the last time I saw her. It seems as if Laci had planned all along to have children and that was understood, going into it. But if you analyze their marriage, it seems that when she got pregnant with Connor, things started going sideways. It breaks my heart because she was trying so hard to have this perfect home for baby Connor to come into. And she had no idea it was a house built on sand that was sinking quickly. No idea. I hope you know that I had nothing to do with it. You know, even if you think I did, don't give up looking for her. Because we need your help bringing her back. Okay, your wife is missing. And Scott's telling me when I interview him I went fishing. I tried to call my wife three times. I called her cell phone, her house, she didn't answer so I'm thinking something's up. Okay, that's spooky and I'm getting a limit nervous. This is unusual. I'm getting a little scared. ???
This transcript has been automatically generated and may not be 100% accurate.