According to reports, the shooter was 20-year-old Adam Lanza. It appears he took his own life after the rampage that left the U.S. in shock.
[ Related: Who was Adam Lanza ]
And while the adults are still struggling to unravel what happened at Sandy Hook Elementary School in Newtown, Connecticut, the students are starting to share their own experiences.
"We heard lots of bangs...we heard screaming," one boy told the journalists. "Then somebody yelled: 'Get to a safe place!' So we went to a closet in the gym."
Watch him describe his escape in this video:
Stephen Delgiudice, the parent of a student at the school, told CBS News that it appears the shooting began in the principal's office. His daughter told him that part of an argument was broadcast over the school's intercom before the shooting began.
Local and state police rushed to the scene and swept the building after reports of the attack came in after 9 a.m. The entire school was searched through the morning as students were evacuated. Reports suggest that two handguns and a .233 Bushmaster were recovered.
"I felt scared and the other kids were shaking," says a third-grade student who was at the school during the attacks.
William Wolfe-Wylie of Postmedia News wrote that a total of 31 school shootings rocked the United States since the Columbine High School shooting of 1999. And this shooting is among the worst.
Tearful President Barack Obama addressed the nation to say that the country has "endured too many of these tragedies in the past few years."
"They had their entire lives ahead of them. Birthdays, weddings, kids of their own," Obama said of the children that were killed on Friday.
After safely making it outside, this little girl was happy to reunite with her dad. Watch her recount the experience below:
And if you are wondering if you should be talking to your children about this tragedy, here's a video that addressees the issue.
Get the latest details about the Connecticut elementary school shooting here.