where tragedy struck in a place where parents thought their children were safe. At least 27 dead, 20 children, 7 adults including the principal. And the gunman killed himself. And all over this town... See More
where tragedy struck in a place where parents thought their children were safe. At least 27 dead, 20 children, 7 adults including the principal. And the gunman killed himself. And all over this town in churches like the united methodist church, the lights are on and they are still open for prayer tonight. They will be all night. People are gathering and leaning on a belief bigger than themselves to get through a belief that is impossible to believe. And a sentiment you see near the washington monument in d.C., The members of the delegation were there. But this is a story about their home, newtown, connecticut, just 20,000 people. This is a place where people know each other. Families know each other. And what happened today is known by all. It's not about how many are lost. It's the age. The reality of these being targeted by a mad man. We now know his name. We know he is 20 years old, adam lanza. He shot his mother in the face, killing her at her home. The looming question, why this man decided to come to this school. He shows up at a place where they are making jirng bred houses in preparations for the holidays and christmas presents. Just kids. A plan in black enters with a vest and mull pl weapons and beginning a massacre. It was a clear, crisp and trouble-free start to the morning at sandy hook. Kids eager for the weekend and the holidays to arrive. It's christmas time, right? Where are we, in terms of christmas planning? Shopping, cookie making. We deck kated the christmas tree. Is the christmas list made? Yes. Sent to santa? Yeah. Ella's class was preparing to make ginger bred houses. When you first got there? It was a regular danchts but at 9:40 a.M., The children's day and innocence is shattered. Sandy hook school, there is someone shooting in the building. We thought something e fell and we herd another bang and we thought that was a gunshot. What do you remember? We got to school. We did everything we needed to and then we heard all this racket. And then we heard say go in your cubbies. We thought something bad was happening. What did the ticher do then? She read us books and talked about things and we played little games in there. While that was going on, your teacher was reading you books and keeping you calm? Yeah. She was kept you calm and read you a story. She read us the "nutcracker" and another book about christmas. How do you find out? We got a phone call from the schools saying the school was on lock down. Lock down? What did that make you feel? Not very good. The police quickly conversige on the school and look for the shooter. The police came in. He is like s he in here? He ran out. That included checking every door, crack, crevice for the school. The main objective was to evacuate as quickly as possible any and all students in the school. It tacks an agonizing hour before it's clear what has taken place inside the school. Next, ambulances are called. Stretchers set up. By 10:30 a.M., They escort students out of the school. Teach eshs are crying. And they are all huddling together and they felt so sad. We all put our hands on other people's shoulders and then our teacher holds the first person's hand and she led us out. Did you keep your eyes closed in. Yeah. When you opened them, where were you? We were walking down to the fire station. The children are taken to the fire department where parents swarm, desperate to find out if their children are safe. It's terrifying. I don't know what happened. Rudd rushing over here and you can't get to where you need to go. And you have to park down here. And walk. When a son or daughterer is found, the relief is immense. I was so happy. I just hugged her. What goes there your mind when you see her? Oh, my god, this is the best day of my life. The worst day of my life. Just great frl nss. Grateful nss. The tears come to your eyes when you know your child is okay. Too many families aren't as lucky. Minutes drag by, no answers in the school. And the worst is obvious. Not all of the reunions between parents and the child will be happy ones. I need units in the school. I got bodies here. By 11:00 a.M., The police give indications there are multiple fatalities inside. By 11:50 a.M., They announce most of the fatalities are children. It is almost unimine able. 27 deaths, 20 children. News of the second worst shooting in u.S. History smothers the country. I know there's not a parent in america who doesn't feel the same overwhelming grief that i do. The majority of those who died today were children. Beautiful little kids between the ages of 5 and 10 years old. They had their entire lives ahead of them. Birthdays, graduations, weddings. Kids of their own. The man responsible for takes these lives, 20-year-old adam lanza. His body found in a classroom after he took his own life. He was armed for war, say authority, carrying two semiautomatic handguns. A sem automatic rifle found in his car. Authorities confused him with his older brother, ryan, because he was carrying his i.D. He shot his own mother in the face before heading to the school. Principal dawn houfsprung, one of those killed. Evil visited this community today. Our hearts are broken today. For the parents, and grandparents, sisters and brothers of these little children and for the families of the adults who were lost, our hearts are broken for the parents of the survivors as well. For as blessed as they are to have their children home tonight, they know their children's innocence has been torn away from them too early. It doesn't happen here. And the six degrees of separations, we know those families. There will be families and friends we know. You know that people got hurt, right? Yes. You know that it's over? I don't know when it was over. And I probably would have never known when it was over. Well, it's over. Okay? You know that now? Yes. And what happened there today happened and it's over. Okay? And you have to be happy that you are okay. Of course, for the seavers, so much why they wanted to come forward, they feel for the families who were not as lucky to have ella come home. The community, this is going to be with them a long time. They share in that grief. I know they do. And the next few day, we are going to be hearing so many more stories of courage from little children and also from these teac who held hands and prayed with the children and tried to keep the tragedy from becoming worse. And I spent the day this afternoon, I spent time with one young woman who wanted us to know what all the teachers do in the school, as she told her story. First grade teacher kaitlin roig and she sur pressed her own fear for the children to say they were going have a christmas. They were going have a hanukkah and come through it toll. It was 9:25 in the morning when katelin roig began class. It was in the morning meaning and it started. What you did hear? The shooti, the first classroom. You did know it was a shooting? I knew it was a shooting, immediately. It was a repetitive sound? Yeah, the type of gun that shoots over and over again. And I heard that and I knew that something was obviously very wrong. And I got up and I closed our door. It wasn't lock sbid told the students we had to get in the back. It was all I could think of. I knew we had to be hiding. How many children? I have 16 student, one was absent today. 15. 15 frightened first graders. One cramped place to hide. You got them in the bathroom? I put them on top of the toilet. And one on top of the toilet. I knew we had to get in there. Were you laying on top of them? We were all very, very close. Did they cry? No -- if they started crying, I would take their face and say, it's going to be okay. Show me your smile. I tried -- and one of my students was saying thing, i know karate, it's okay. I will lead the way out. Trying to be courageous and take over. And I said, we need to stay here right now. We have to be calm and still and quiet. In the first grade, they knew. We were right there. I mean, we're the first room. We heard it so clearly. They knew something was obviously very wrong. Many member of the emergency units from this town -- did you tell them to be quiet? Yeah. Did you tell them -- I told them we had to be absolutely quiet. I was afraid he could hear us and just shoot the door. I said, we have to be absolutely quiet and we have -- I said, there is a bad guy throughout now. We have to wait for the good guys. As the teacher, I'm the protector. For them to say, I just want to go home and have christmas. Was trying to tell them, you will. We will be okay. You have to think positive. They said to you, we want to go home for christmas. Oh, yeah. Yeah. M mm-hmm. I just want to hug my mom. Things like that. They were just -- it's heartbreaking. You know? And you are hearing -- I have never been a part of something obviously never near this traumatic. So I'm hearing the gun fire in the hallway and I'm thinking, in my mind, I'm the first classroom, I'm thinking, we're next. And I think, as a 6-year-old, 7-year-old, what are your thoughts? And I'm thinking that I have to almost be their parent. Like, I have to tell them -- i said to them, I need you to know that I love you all very much and it's going to be okay. Because I thought that was the last thing they were going to hear. I thought we were all going to die. I don't know if that is okay. I wanted them to know that someone loves them and I wanted that to be the last thing they heard. Not the gun fire in the hallway. It's just horrible. Horrible. I just wanted me and my kids to live. I'm not a hero. I'm just thinking, where can we go? It happened to be the bathroom. I wanted it to be okay and I am so sad that there are people in the situation who are not okay. And my heart goes to anyone who knew them and was part of their lives. I can't imagine. How you did know you were going to be okay? What finally happened, the gun fire stopped. The police came and started knocking and obviously, I was completely beside myself and i said, I don't believe you. You need to put your badges under the door and they put their badges under the door and I'm like this doesn't look like a real badge. You don't believe the badges. I said, if you are a really a police officer you could have a way to get in here, would have gotten it. You would have found the keys and he found the keys and he Down the hill from the school, dozens of parents gather at the fire house to see if their children had survived. What do you say to your children as you walked into your fire house? We are okay. We are okay. Do you wonder who did this? Absolutely. And why. Why? You know. They're innocent children. And again, chris, she wanted to say that she knows every single teacher in the school was doing what they were going for the children they love. And she raises the question, why? Why did the children have to be put in this position. And it brings us to the person who deserves the least attention. And the gunman, adam lanza. We try to look at why this happened and hopefully it's a window to an understanding how to not make this happen again.
This transcript has been automatically generated and may not be 100% accurate.