INSIDE EDITION got the first look inside the apartment of movie massacre suspect James Holmes.
On his wall, there's a poster for the DVD, Soldiers of Misfortune, all about the world of paintball warfare.
It's believed Holmes tossed smoke bombs 15 minutes into the movie, The Dark Knight Rises.
INSIDE EDITION found dozens of videos on YouTube talking about how paintballers can use smoke to avoid detection and create chaos. And there are demonstrations on how to use them.
INSIDE EDITION asked Fire Chief Robert Hughes of the Nassau County, New York Fire Academy to demonstrate.
He said, "Pull the pin and just drop it and throw it."
The smoke makes visibility nearly impossible within seconds. You can imagine the terror and confusion inside the movie theatre in Aurora, Colorado on that tragic night.
Chief Hughes said, "You can buy these in paintball shops. You can buy them on the internet. And obviously they are going to distract people."
On paintball websites Tuesday, backers are upset about any connection between their sport and James Holmes.
At least one paintballer isn't shocked. On the website, Paintball Nation, a user under the alias of Gator 50 wrote, "When you show interest in a sport that's main focus is shooting people, the general public tends to make these connections."