Fish was not the first or the last murderer to use the common good as subterfuge. The men who ran Boys Town in the 70's would sometimes murder 20 children at a time after yearlong charades to convince their families that they had died of cancer or some other illness/accident.
Nobody ever went to prison for their direct involvement in what was really happening. There were a lot of cover-ups just to put a stop to it that compromised justice to this day.