Get all the news you need in your inbox each morning. USA TODAY reported that an AR-15-style rifle was used in the ...

A Colorado Springs police officer at the annual Medal of Valor ceremony in September. The city police department has responded to several mass shootings in recent years, and many officers now ...

The images may disturb some people. The wounds show the lethal force of the AR-15. But they are rarely seen. The gun is the weapon of choice for many mass killers. It works with brutal efficiency.