Joseph M'Ilvaine. This renowned Philadelphian recorder stated, ""It is not safe to rely exclusively upon voluntary communications from private citizens, because regularity cannot be secured, and because inexperienced individuals are constantly liable to deception and mistake." After which, he stated that the best solution was, "a class of officers . . . moving rapidly and quietly from place to place as the exigencies of the service may require."
Prior to the 1840s, the average constable was deprived of the opportunity of doing their job to its full effect as their jobs were being dominated by new assigned patrolmen. In fact, their jobs were now given to these patrolmen who, seemingly at the time, left them with nothing to do. However, the constables were persistent as they apparently loved their jobs and endeavored to continue with it. Therefore, by the 1840s, they designed an area within the policing vicinity where they investigated crimes subsequent to it being committed, as they had developed a profound and detailed knowledge of the art of policing. However, the proposal to incorporate detection into the campaign to reform law enforcement was rejected as detection was not apart of preventing a crime from occurring, but rather a study of how it happened.
This was unfortunate, as detection was of utmost importance due to the fact that it assisted in verifying facts about properties, that is, the study of its true meaning, ownership, etc. and learning the skill of thieves who continuously confiscated people’s belongings. Thieves of the era designed new ways of undertaking their unlawful deed on a regular basis. Therefore, the detectives’ intervention would be useful as they would study these criminals, thus, learn their strategies. This has been proven to be productive, as examples of detectives catching criminals in their act, were recorded.
The prevention of detection affected the constables, as they were deprived of the opportunity to capitalize on their idea, and also the citizens who were being constantly robbed by consistent thieves.
(Taken from David R. Johnson’s “Policing the Urban Underworld”, Professional Thieves and Policing)
I agree that without the study of detection, many crimes especially that of thievery would go unchecked and unpunished. It is unfortunate that this area of expertise didn’t exist until the 1840s, but as you stated before the constables were persistent and succeeded in doing their job.