Holly Yan

(CNN) — Bone-chilling Arctic air gripped much of the eastern United States on Saturday, while lake-effect snow threatened to leave some

(CNN) — Bone-chilling Arctic air gripped much of the eastern United States on Saturday, while lake-effect snow threatened to leave some

What we know so far • UnitedHealthcare CEO Brian Thompson was shot and killed in midtown Manhattan Wednesday morning in an apparent targeted

(CNN) — At first glance, the assassin seemed too meticulous to be an amateur and too careless to be a professional.

‘What surprises me is how well planned the actual attack was, and at the same time how sloppy the killer was in his movements.’

By Karina Tsui, Holly Yan and Nicole Chavez, CNN(CNN) — The pre-Christmas buzz and serene sense of safety at Abundant Life Christian School were shattered Monday when a student pulled out a gun and opened fire – killing two people, wounding six others and prompting a second-grader to call 911.

Emergency vehicles are parked outside the Abundant Life Christian School in Madison, Wisconsin, following a shooting on December 16.

(CNN) — Police are investigating why a teenage girl brought a handgun to her small Christian school in Wisconsin and opened fire, killing two people and wounding several others a week before Christmas.

To help avert potential school violence, students and staff need to know certain warning signs – and feel comfortable reporting them.

A “mass casualty incident” has occurred in the French Quarter of New Orleans, emergency officials said early Wednesday.