who is the daguerreotypist, and what is he suspected of doing

Mr. Holgrave

A boarder at the House of the Seven Gables, this young man is Hepzibah Pyncheon's only friend. He is currently employed as a daguerreotypist, but has moved from profession to profession and seems likely to do so again. He is largely a mysterious man, suspected of engaging in some Black Art in his room, and he closely monitors the Pyncheon family that remains. He has been studying the Pyncheons in order to publish a family history, and in the end reveals himself to be a descendant of Matthew Maule.