Espionage, for the most part, involves finding a person who knows something or has something that you can induce them secretly to give to you. That almost always involves a betrayal of trust.
I think there is something about coming to a city to work that puts you in touch with it in a different way.
There have been 14 versions that I can find of Burke & Hare movies. They have all been horror films and all the movies have taken place in Victorian times, which doesn't make any sense.