Transcript for Newtown, Connecticut Shooting: Timeline of Events at Sandy Hook Elementary
And such a sad morning here in newtown, connecticut. I'm joined by elizabeth vargas in new york. And right behind me, the sandy hook firehouse, where moms and dads came to learn about their children. Many sleeping her through the night. And this headline from "the hartford courant" says it all. Here's what we know right now. The shooter, adam lanza, 20 years old. He also shot his mother before coming to the school. The bodies of the children slain were still in the school. And families were notified overnight. The names will be released this morning. You're going to look at stills from the vigil right here in sandty hook last night. A scene of so much unimaginable grief. There they are right there. The families, the communities coming together to pray for their children, those who were lost to remember them. Try and comprehend what happened here in newtown, connecticut. My "gma weekend" colleague, dan harris, has been here from the beginning, covering this tragedy. And you watched it unfold through the day yesterday. We did. George, just when you thought the mass shootings, just when you thought they wouldn't get worse or more shocking, along comes adam lanza, who began his day by killing his mother, and ended it by storming that school. And of all the people he shot, there was only one survivor. 9:40 a.M., Reports of gunfire at sandy hook elementary. Sandy hook school. Caller is indicating that she thinks there's a shooter in the building. Reporter: Adam lanza wore a bullet-proof vest and was carrying three semiautomatic weapons including a rifle. I felt a little sick. Reporter: Within five to ten minutes, the first s.W.A.T. Teams arrive. I need units in the school. I got bodies here. Reporter: Officers helped teachers lead several hundred students to a nearby firestation. When the policemen came in to get us, he told us to close our eyes. And like on the picture on the news, do this. Reporter: At 10:30 a.M., president obama was briefed on the situation, as police discovered a second crime scene. Lanza's mother was found dead. Police say adam lanza shot her before he stormed the school. Around noon, abc news learned that lanza had killed 27 people, most of them children, before turning the gun on himself. Shortly after 3:00, the president addressed the nation. 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. Reporter: By 7:00 p.M., This little town had settled into an all-too familiar post-massacre routine, with prayer vigils. May god bless the adults who lost their lives today. Reporter: Overnight, police engaged in the horrifying work of identifying the bodies and then notifying the families. Now, the big question in this investigation is why? What was the suspect's motive? George, if past is prologue, we may get an answer. But it will be deeply unsatisfying. Let's get more from elizabeth in new york.
This transcript has been automatically generated and may not be 100% accurate.