Allan Pinkerton

“There is no branch of detective science that is so important and so difficult to carry out as that of shadowing.”

“A detective without imagination is a provincial plodder.”

“The professional thief is a man of business, and his business is to steal.”

“Next to the confrontation of the victim and the perpetrator, the photograph is the most convincing evidence.”

“I have no sympathy for the Devil.”

“Crime is but a disease—a moral distemper; and the machinery for its detection and punishment is what the physician is to the physical maladies of the body.”

“The detective and the criminal are cousins.”

“The eye that never sleeps.”

“We never sleep.”