Who was Jack the Ripper, and why wasn’t he captured? I do not believe, like some of my contemporaries, that the police of the day were incompetent.
There may well have been some officers who did not perform their duties as well as they should have, but on the whole, the detective force and the constables on the beat did their very best.
The reason they did not capture Jack was that they were looking for the wrong type of man. They were not the results of domestic disputes and were not committed as a result of robbery or rape, so the police did not understand them.
The idea of someone killing for nothing more than the pleasure of the deed was previously unheard of, and when the police realized that this was indeed the case, they looked for a slavering maniac whose mind was diseased and whose emotions were out of control.
The murders were inhuman, so the killer had to be inhuman too. I contend that although extra constables were drafted and at times the streets must have been crawling with officers, they were all looking for someone who stood out from the crowd, someone whose behavior was suspicious or erratic, whereas Jack simply didn’t behave like that.
The police probably also believed that the murderer would be reeking with blood, but the method Jack usually employed was to kneel to cut the throat of his victim while she was lying on the ground and to cut in a direction away from himself.
Thus, in most cases he would have escaped almost unmarked.