Instead of hearing the usual announcements over the intercom Friday morning, the 630 students at Sandy Hook Elementary School heard something else: the murder of their principal.
"Yeah, yeah, she was crying. I thought she was screaming," third grader Tori Chop told "Good Morning America." "That's what we heard over the loudspeaker."
The gunman, identified by law enforcement as 20-year-old Adam Lanza, who once attended Newtown High School, started his rampage in the school's main office around 9:30 a.m., where school principal Dawn Hochsprung, 47, had reportedly come out of a meeting.
"We kept hearing gun noises and 'put your hands up'…we kept hearing that," said Chop.
Mary Ann Jacob, the library clerk at Sandy Hook, heard the sounds too.
"I called the office because I thought it (the intercom noise) was a mistake," Jacob told AFP Saturday. "The school secretary answered and she said there was shooting. I'm amazed she answered the phone."
The New York Times reported that Lanza used a Sig Sauer and a Glock, both handguns. Police also found at the scene a Bushmaster .223 M4 carbine, a rifle.
Law enforcement officials said some of the guns used in the attack may have belonged to Lanza's mother, Nancy Lanza, 52, who he fatally shot in the face at their home before jumping in her car and driving two miles to the school. His mother had four legally registered weapons.
According to the Hartford (Conn.) Courant, Lanza dressed in black fatigues forcibly entered the school, which serves children aged 5 to 10, by blasting as many as a half-dozen shots through the front door.
Theodore Varga was in a meeting with other fourth-grade teachers when he heard the gunfire, The Associated Press reported. He said someone had turned on the intercom so that "you could hear people in the office. You could hear the hysteria that was going on. I think whoever did that saved a lot of people. Everyone in the school was listening to the terror that was transpiring."
The chilling details about the opening moments of the blood bath in the Norman Rockwell picturesque community of Newtown come as the country grieves in the aftermath of the second-deadliest school shooting in U.S. history. Lanza ultimately killed at least 27 people, including himself. Lanza is believed to have acted alone, and the killings were limited to two rooms in one section of the school.
The death toll exceeded that of one of the most notorious U.S. school shootings, the 1999 rampage at Columbine High School in Littleton, Colorado, where two teenagers killed 13 students and staff before killing themselves.
In fact, Friday's massacre may be the largest school shooting of young children in the world, said Larry Barton, a professor at The American College in Pennsylvania whose three decades of research includes studying violence in workplaces, public spaces and schools.
Mass school shootings have often targeted high school or college students, he said.
"This is among the most diabolical crimes, to kill kindergarten-age children," Barton said. "It's very rare."
Gov. Dannel Malloy put it another way.
"Evil visited this community today," he said.