He / she may not even be killing the cats!!
i think they have come up with an excellent scare tactic, we have loads of cats roaming our streets and i personally am not a cat person but if they are kept out of mischief then great. They do cause alot of havoc when they are left to roam freely as are dogs i will admit, i don't think any pet should roam the street. i would fully expect someone to complain if my dog got out and disturbed someones sleep all night or whatever damage, i would also apologise profusely and offer to rectify.
I think the biggest problem is that people have come to think that cats naturally do things like roam the streets and so forth. I put to you my workmate, she owns a cat and has been asked by her neighbours to keep it under control, she did not. The street members called council and she was sent a letter, to which she got angry and took it up with her neighbour and was fuming the next day at work which is why i know what went on lol. I asked her "then what are you going to do, are you gunna keep him inside or something?" to which replied "NO hell no it's a cat, its what they do'