Adam Lanza blasted his way into the Sandy Hook Elementary School. He fired a half-dozen thunderous rounds from a semiautomatic rifle to open a hole big enough to step through in one of the school's glass doors.
Once inside, he had to make a choice.
Principal Dawn Hochsprung's office was straight ahead. To the right, 25 or so children were rehearsing a play in the school cafeteria. To his left were the first-grade classrooms.
Lanza turned left.
It was about 9:40 a.m. Friday. In just minutes, Lanza — a withdrawn, emotionally detached 20-year-old who lived with his mother and is said to have played graphically violent computer video games — would kill 26 people in the country's second-largest mass killing. Dead were 20 children, four teachers, the school principal and a school psychologist. Earlier in the morning, Lanza shot and killed his mother, Nancy, perhaps the only person with whom he was socially engaged.
Lanza shot himself as police arrived, sirens wailing.
Late Saturday, an army of police detectives continued to interview members of Lanza's family and others who knew him, searching for answers to innumerable questions — chief among them what could have driven anyone to such violence.
Several sources in law enforcement and elsewhere provided what they said was the most current information on how the events leading to the school shootings unfolded.
On Friday morning, as Lanza turned left, toward the first-grade classrooms, Hochsprung and school psychologist Mary Scherlach, shocked by the sounds of gunfire and shattering glass, bolted into a corridor from a conference room across the hall from the classrooms.
He shot them both with the rifle.
The first classroom that Lanza reached was that of teacher Kaitlin Roig. Alarmed by the gunfire, she had hidden her students in a bathroom and closed her classroom door. For reasons that could not be explained Saturday, Lanza passed by Roig's classroom.
The classroom he chose to enter was substitute teacher Lauren Rousseau's, where he proceeded to systematically shoot everyone inside — the 14 children who investigators believe were huddled and clutching one another in fear, Rousseau and a special education teacher who happened to be in the room. Rousseau was filling in for the regular teacher, who was out on maternity leave. Rousseau had been teaching at the school for six weeks.
"There were 14 coats hanging there and 14 bodies. He killed them all," said a law enforcement officer involved in the case.
Lanza next arrived at teacher Victoria Soto's classroom. Soto is believed to have hidden her 6- and 7-year old students in a classroom closet. When Lanza demanded to know where the children were, Soto tried to divert him to the other end of the school by saying that her students were in the auditorium.
But six of Soto's students tried to flee. Lanza shot them, Soto and another teacher who was in the room. Later, in their search for survivors, police found the remaining seven of Soto's students still hiding in the closet. They told the police what had happened.
The two teacher's aides who were killed were Mary Anne Murphy and Rachel Davino. It was unclear which aide was in which room when they were killed.
The first officer to arrive at the school found Lanza's body near the door of Soto's classroom.
The intense violence lasted about 10 minutes. Lanza fired at least three, 30-round magazines with deadly accuracy. Two of the people he shot survived. All of the victims were shot multiple times.
"I did seven (autopsies) myself with three to 11 wounds apiece," Chief State Medical Examiner Dr. H. Wayne Carver III said Saturday. "Only two were shot at close range. I believe everybody was hit (by bullets) more than once."
Investigators believe that the violence began even earlier that morning in the 4,000-square-foot home on Yogananda Street where Lanza is believed to have lived with his mother. He hasn't spoken since 2010 to his brother, Ryan, or his father, Peter, who has a home in Stamford and another in New Jersey, the sources said.