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.