Inside law enforcement's training for dealing with an active shooter

Posted at 11:20 PM, Dec 13, 2016
and last updated 2016-12-14 23:34:48-05

It can happen anywhere and at any time - an active shooter putting lives at risk

Now, we're going behind closed doors with Homeland Security to see the incredible - and realistic - technology they're using to prepare police and federal agents for any situation.

It's all designed to save lives.

Simon Shaykhet brings you the story that will change what you think you know about active shootings in the video player above.