415 killed in school shootings since Columbine. At the time, the massacre in the suburban Denver suburb of Littleton was the deadliest school shooting in U.S. history.

But determining exactly how many "school shootings" have occurred in the U.S. since Columbine is complicated. It depends on how the term is defined—and can range from just eight to more than 2,000.

The analysis looked at more than 300 school shootings that have happened in the U.S. since Columbine, excluding any incidents at college or university campuses. Researchers found some compelling ...

DENVER — Hours after she escaped the Columbine High School shooting, 14-year-old Missy Mendo slept between her parents in bed, still wearing the shoes she had on when she fled her math class.

Columbine survivors can’t believe that the shootings haven’t stopped 25 years later. Since 1999, the name of a Colorado high school has been tragically enshrined in the public consciousness ...

It’s been 25 years since Columbine. ... And data my colleagues and I are gathering show that there have been nearly 350 intentional school shootings in K-12 public schools since 2015, ...

How survivors of Columbine are coping, 20 years later. It has been nearly 20 years since the first mass school shooting in the U.S. -- the shocking tragedy at Columbine High School in Littleton ...

One of the most infamous school shootings in U.S. history, Columbine left a deep wound ... In the quarter-century since two gunmen at Columbine shot and killed 12 fellow students and a teacher ...

Saturday marks 25 years since the mass shooting at Columbine High School. David Hogg, who survived a massacre at his high school in Parkland, Florida, joins CBS News to discuss the ongoing push ...

DENVER — Hours after she escaped the Columbine High School shooting, 14-year-old Missy Mendo slept between her parents in bed, still wearing the shoes she had on when she fled her math class. She ...

D ENVER (AP) — Hours after she escaped the Columbine High School shooting, 14-year-old Missy Mendo slept between her parents in bed, still wearing the shoes she had on when she fled her math ...