Now, this is a fun idea.
I wonder if a Chicago assassin would fly. Black Suit, black tie, a black hat and thick sunglasses, the stereotypical G-man. An okay scrapper, and fairly good with a gun, but his specialty is accidents. Accidents and suicides. That's what his killings look like. He sabotages, he sets up death traps so in most cases, his victim and his person aren't even in the same room. He also enjoys jazz, rhythm and blues, and a little rock.