Updated

A deadly shooting at an Indiana grocery store could have been much worse if not for the quick actions of two police officers who relied on training that has become commonplace since the 1999 Columbine shootings.

Elkhart officers Cody Skipper and Jason Tripp arrived at the store within three minutes of a 911 call Wednesday night. They needed about 60 seconds to locate and fatally shoot the gunman, who had killed two people and was threatening a third.

In the past, officers often waited for backup. But many experts agree that quicker responses are needed. Most officers are now trained to go into active-shooter situations right away and alone if necessary.

Some professionals still advise waiting. Security consultant Chris Grollnek says doing otherwise amounts to a "suicide mission."