I totally believe (& think that it is pretty much confirmed) that the tattooed zombie is indeed "Ink". I think the coincidence of the infection breakout and him being transferred to a mental facility in LA shows that the infection may be connected to him. Either he is connected with the infection, or his psychopathic killing spree that he was sentenced for has something to do with why he is a smart zombie.
Him to being able to lead and control the zombies leads me to believe that he has a connection to the outbreak. Perhaps his sentencing is specifically tied with it. Just a thought