Mammon is the Biblical term for wealth and riches, specifically the evil influence the pursuit of wealth and Earthly riches can cause; also sometimes used to refer to the worship of riches as a false idol. A Middle Age era religious text lists Mammon as one of the seven Princes of Hell, a demon that personified covetousness, greed and desire for material things and money.
While interviewing the victim's roommate, the roommate mentions going to a bar in "DUMBO," which means "Down Under the Manhattan Bridge Overpass." It's a neighborhood located in the Brooklyn, where the Bridge links the Boroughs of Manhattan and Brooklyn.