I don't know any more of the story other than what is provided by ABC12 News. The dummy was wearing a fake badge though...
http://www.abc12.com/story/22983041/fbi-arrests-man-who-had-body-armor-guns-at-trillium-theater
http://www.abc12.com/story/22983041/fbi-arrests-man-who-had-body-armor-guns-at-trillium-theater