We count six cops in total throughout this story. All but the sixth one has no interest in arresting Soapy at all. We don't learn much about these six men, but we do know they are included in the four million people (the population of NYC in 1904) O. Henry was trying to reach and represent. Notice that the policemen are shown fairly neutrally, not particularly bad or particularly good. The policemen shown are simply men trying to do their jobs.