The "prison mustache", as popularized by members of the Aryan Brotherhood prison gang is an exaggerated version of the Handlebar Mustache. The ends of the "handlebars" are allowed to grow very thick and bushy. It somewhat resembles a long, thick goatee beard with the point of the chin shaved.
That guy is definitely an ex-con. Look at his prison mustache and his Nazi Low Rider tats.