What does this image of Alan Pinkerton, seated left, in front of a standing Abraham Lincoln indicate about one service the Pinkerton Detective Agency provided in the mid 1800’s? Responses Pinkerton was collecting mug shots of 19th century criminals. Pinkerton was collecting mug shots of 19 th century criminals. Allan Pinkerton traveled extensively. Allan Pinkerton traveled extensively. Pinkerton taught his employees how to study faces. Pinkerton taught his employees how to study faces. Pinkerton was instrumental in protecting the President of the United States and his agency was a forerunner of the Secret Service.