John Ferrugia discusses STEM School attack with Judy Woodruff on PBS Newshour.

Madalena DeAndrea was only two years old in 1999 when the Columbine High School massacre happened, but she's heard stories about that terrible day her entire life.

Twenty years have passed since two students murdered a dozen classmates and a teacher at Columbine High School near Littleton, Colorado. But curiosity about the campus seems to be intensifying as the years go by, according to the man in charge of securing the school

The book authored by the mother of one of the Columbine High School shooters has generated more than $400,000 in donations for mental health charities, according to records obtained by Rocky Mountain PBS. Klebold did not profit from the publication of the book, instead donating the proceeds to mental health research.

A student reflects on red flags ahead of the Columbine High School shooting 1999. What are the warning signs? An expert explains what behaviors might be warning signs.

The Moore brothers have nearly 75 years of trauma surgery experience between them. The pair grew up with guns, but they have differing opinions about who should have access to semi-automatic rifles, like the AR-15.

A man who fired his gun on a school campus as a 14-year-old in 2003 said he regrets that he thought that was the best way to protect himself. “If I had the wisdom and knowledge I have now, I definitely wouldn’t have made the decision I made," he said.

Colorado has become the 15th state to allow temporary removal of firearms from a person who is determined to be a threat to self or others.

The battle over the controversial “red flag” gun bill overcame its first hurdle in the Colorado Senate Friday on a party line vote as members of the Democrat-controlled chamber heard impassioned pleas from gun rights advocates to kill the measure. The measure now moves to the appropriations committee and will move to the Senate floor if approved.