Authorities gave few details on exactly how the attack unfolded, saying they are keeping some details "close to our chest" as they continue to investigate the crime scene. But police radio traffic indicated the shooting lasted only a few minutes.
Officers arrived instantaneously, immediately entered the school, breaking windows and searching it completely before finding Lanza dead, Vance said. Later, at least three guns were found: a Glock and a Sig Sauer, both pistols, inside the school, and a .223-caliber rifle in the back of a car. Vance said at a Saturday morning news conference that investigators were tracking the history of each of the three weapons recovered. Lanza also apparently tried to buy a rifle several days before the shooting, but did not succeed.
A law enforcement official said Adam Lanza was known to have some kind of personality disorder. His older brother, 24-year-old Ryan, of Hoboken, N.J., was being questioned, had been extremely cooperative, and was not believed to have any involvement in the rampage and was not under arrest or in custody, but investigators were still searching his computers and phone records. In some early confusion, Ryan Lanza was initially named as the shooter by police.
Ryan Lanza told law enforcement he had not been in touch with his brother since about 2010. Peter Lanza, father of Adam and Ryan, was informed about the shooting Friday afternoon by a reporter who was waiting outside his home in nearby Stamford.
Witnesses described a chaotic scene inside the school as the shooter opened fire, eventually killing 20 students between the ages of 5 and 10. One teacher was shot in the foot and survived, and police believe she will provide critical evidence.
"I was in the art room and we heard gunshots so we had to close the door," said Venesa Bajiraliu, a 9-year-old fourth-grader. "But ... one of the doors didn't lock so we went in the art teacher's office. And she called her husband to call 911, and the police came and when they came we heard on the loudspeaker a scream, and then they came and we went with them,. And they said to close our eyes so I closed my eyes, and then when we went outside of the school we can open our eyes."
When President Barack Obama addressed the nation just after 3 p.m. on Friday, he cried.
"I know there is not a parent in America who doesn't feel the same overwhelming grief that I do," said Obama, who paused several times during his remarks to compose himself and dab his eyes. "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."
He promised action to prevent such tragedies again but did not say how he would do it.
Gov. Daniel Malloy spoke briefly at a press conference on Friday and said, "It's a tragic, tragic scene." Later in the day, the somber governor said "evil visited this community."
Late Friday, police remained at the school, gathering evidence. Meanwhile, families affected by the shootings turned to each other and to faith community for comfort. Thousands gathered at church services to show support for the families who lost loved ones.
At St. Rose of Lima Roman Catholic Church, people filled the pews, the front yard and nearly spilled out into the road. Children came carrying stuffed animals.
Megan Olszewski, a 14-year-old freshman at a nearby high school, was in the auditorium when her school went on lockdown and students hid in between seats. She said they were told there had been a shooting at the elementary school, and when they heard the death toll was 27, "it was horrific."
She said classmates said they wished it happened at the high school instead because they believed they might have been able to stop it.