It's Michael Kirkland. There is a William Blake painting: The Brace of Partridge, but i think it doesn't refers to Partridge (he was a red herring). In the painting, there are two birds, and i think that is a referring to a twin. Maybe Stiles was Michael's mentor (Bob thought he was RJ), he maybe has the same creepy voice, as Bob. He could've shake his hand with Patrick (maybe it wasn't Bob), so some way he is on the list.