Investigation about cat poisoning

Hello,

in our village there are every autumn a lot of cats poisoned. We lost already three fury friends and our neighbour even 14 cats, who lives here longer than us. They are all free strey animals, that we feed and care for, when they need something. This week they killed one of our loved one, and I am freaking out about this. And another cat that came around often was found dead one day later and we also found two kittens dead the same street a bit more further. It seems like a planned murder. Our sweetycat friend showed symptoms of phosphor  poisoning (extremely small pupils at night, epilepsia, drooling, choking, disoriented, he tried to poo it out but couldn't) and it was very fast, we found him still aware and agitated until he did his last heartbeats it was one terrible hour of us trying to save his life with giving him oil to drink with a syringe, and trying to make him vomit with saltwater. 
We are extremely shocked and frustrated. Since the last time our cat was poisoned last year, we made an effort, to actually buy cat food and not just give them our left overs, so they wouldn't need to eat poisened **** because of hunger. For the next time we will get emergency medication now and learn from a vet how to use it. If there are any cats left in this village   .... We found local animal rights groups, that can give us leaflets to spread in the village and we found a vet student that wants to teach us for emergencies. The women, we talked with, said, that it can actually really be everyone. She knows about a case, where they found the person, who owned 5 dogs and cared well for them actually poisened all other dogs in the neighbourhood around, because she hated them pooing in front of her house....people are just crazy...

About calling a vet: the next vet would be 20 minutes far away. With such a heavily progressing poisoning, he wouldn't have enough time, to do much. We called the vet, and he tried to give us help over the phone, which is actually almost impossible if you don't have any medications available and no proper diagnosis (we didn't see what he ate, we walked around the neighbourhood and couldn't see anything suspicious).

But HOW to find the murder???
We think about several strategies:
- hidden investigation on our neighbours to find out who it was and take revenge, secretly
- open investigation to make sure the village knows that people actually do not ignore that anymore, make the murder openly known and then take revenge
- we don't want to involve police, because they would not do anything and we don't want more police in the village
- invite an animal NGO to make information events for animal friends in the village about poisoning and get information material that we spread all over the village, to unite the animal friends here, so it get easier to share information, help each other etc...

In this village, we have plenty of stray animals and a lot of animal lovers, they all care and pet the stray animals, give them water and food and health care if needed. But there also seem to be people on a mission to "clean" the village from any animal. They don't do it openly, cause they are afraid of the people punishing them for it. But we want to create an atmosphere of people not doing it anymore at all. 

Are there any people in this forum who know how to investigate on this in a good way? Of course there are also ideas like hiring a professional detective or installing cameras all over the area, but this is expensive, we are all poor here (and my boyfriends is chronically ill). We have barely enough resources to take time to deal with this at all. But we will do our best we can. 
ANy experiences with that? Any success stories of finding the murder? Any smart questions to ask or think about? Please share!!
 

It seems you've covered all the bases. I would have recommended motion detection cameras or lights--if the light comes on, maybe the murderer would run away-but maybe lights are cheaper?
You might also spread the word among children about how horrible killing cats is, maybe they'll direct you to the murderer.
SAWA is trying to change the attitudes of people who believe that animals are for working purposes only and when they can't work (guard the farm, hunt and kill rodents) they are abandoned or killed. SAWA first did it at the high school level, but that didn't work. Now they are working with younger children. (I vacationed in Greece about two years ago and visited SAWA's farm in Santorini.)
Good luck!

Yes it does sound as if you have covered everything, although what comes to my mind is if somehow while you are educating the people, you can also use a kindness and understanding approach too, let everyone know that you do understand that it may bother some people to have cats pooping around where they live, and wandering, etc.

That if the cats do bother them to please let you know and whether or not they admit to being the murderer(s), you may actually work to keep the cats away from them somehow.

Which means assisting the killers rather than punishing them.

If there is some way to contain the strays a bit, where they are fed and cared for. 

Not sure what's possible to do in your home/village situation, but observing who chases cats away from them, or you clearly see is not befriending them, likely will be the culprit (s).

This is a tough situation for sure. 

Here, we would use cameras/surveillance to watch.

The only other way I can think of is to feed them more, so they are never out looking for food elsewhere.

I know on my cat route, they are all so well fed that they never go into garbage, etc which keeps the business owners happy and the cats are not considered a nuisance.