The shooter has been implicated as a member of Occupy Wall Street’s Black Bloc division. Here is an article which details what they know about him so far:
More Signs Point to James E. Holmes Having Been Occupy ‘Black Bloc’ member
Some rambling blog posts and a few poorly put together YouTube videos isn’t exactly what I would call conclusive evidence. And that picture of that OWS protester being arrested in NYC doesn’t look anything like Holmes. YMMV.