My second thought was to people of that area - don't let your cat out!!! Cats can live a full life indoors. Look at the one who gets peanuts out of a jar!!

1. The affected area is very tightly confined. It's a small zone!
2. The type of crminal activity demands a lot of discrete behaviour. The perp is living within that triangle or very close.
3. To be discrete, I doubt the guy is roaming around at night chasing cats. Rather, he's got a trap set up with a can of Whiskers® in his backyard (er... rear garden since this is the U.K.) and letting the victims come to him.
4. Cats do roam, but the roaming areas aren't all that large... aim for the centroid of the triangle as a starting point. The perp doesn't have control over where the cats roam in from, so the further one gets from the triangle centroid, the less likely it is where
to find the perp. It's not impossible that he'll be on the outskirts or even outside the traingle, just a LOT less likely.
5. Start interviewing residents house by house, surveying who lives there.
6. Who might harm cats? young psychos, satanists, wild bird lovers, some super serious flower gardeners, people who raise dogs for fighting, &c. Ask local kids who the creepy neighbors are. Group each house into "liklihood bins" -- VERY UNLIKELY, UNLIKELY, POSSIBLE, LIKELY, or whatever.
7. 50 is a huge number of cats for a developing psycho to take out before moving on to something else. No other animals falling victim? -- The guy specifically hates *cats*, so concentrate on who that might be rather than sadists in general.
8. I think tormented teenagers less likely. Whoever is doing this has a lot of privacy and probably operates alone. If it's teenagers, the parents are *really* absent and oblivious. There is probably a trap set up and the perp operates frequently at night. Juvenile delinquents are *possible*, but maybe less likely than an adult with his own place.
9. Probably a single person with a lot of privacy and no accomplices to start talking. A couple is possible, but less likely, and any more even less likely.
10. My prime profile -- a middle aged male bird lover or flower gardener who lives alone. Look for the how with the fenced in backyard and a LOT of bird feeders.

Seriously, this isn't an enormous area for the RSPCA to investigate (at least some preliminary legwork) if the police are claim they are "too busy". It wouldn't be too tough to identify a half-dozen "high probablilty" suspects and park a surveillance van watching how active their homes are at night (look for lights on and off in the middle of the night). This activity must be going on at night since the cats roam most then, are unsupervised for hours, and not many prying eyes about.

When you come up with a couple "likely profile" people who ALSO live near the triangle center and who are ALSO busy at night, you should watch them like a hawk and try to get some real evidence on them. This honestly shouldn't be too tough to figure out -- there's a mountain of geographic data already. Just track 'em down and stop thinking about kooky non-likely supernatural or animal predator explanations.

Is this the same area I read about on Itchmo about a year ago? If it is, then it's for sure someone who hates cats and is "doing away with them". In the article I read before, someone trapped dozens of cats in this neighborhood and dumped them far out into the countryside. As if that wasn't bad enough, they sent letters to everyone in that area saying they got rid of the cats and will keep doing so as long as people let them keep roaming loose. Just horrible!

Look, it's not going outside that's dangerous for cats so much as it is letting them get off your property. If someone does harm to your outdoor cat on YOUR property, then you have some legal recourse. Not so if the cat is harmed OFF your property.

I'm so sick of hearing people whine and cry about their cats getting hurt and killed when they allow them to run loose and get in the road or fall victim to cruel people and wild animals.

If you don't keep your cat on your own property when it's outside, YOU are the one who is at fault if something happens to it.

Hmm...

Also, that A Softer World story is cool. I ran across that just a short time ago.

Still, I'm completely amazed that these people still let their cats outside!!! The owners are pretty stupid and neglectful of their pets' well-being to do so. Would you let your kids roam around outside if dozens had disappeared prior. Stupid asses.

Literally.

http://www.neatorama.com/2007/06/21/how-to-get-rid-of-a-critter-proble m/