Someone I know, a while ago, fly tipped a cat.
Apparently it was being a wee shit and kept on breaking into their house by either accessing upstairs windows or breaking their swanky microchip catflap (at £70 a time), It would come in terrorise their cat, eat it's food and spray everywhere. It was doing it to a lot of the neighbours houses, had broken stuff from their windowsils etc. People had spoken to the owner and asked if they would get it neutered to see if that would help but they weren't receptive. It wasn't causing them a problem just everyone else.
Anyway, person I know got hacked off after flap broken for 2nd time, house stinking of cat pee, terrified pet and his toothbrush knocked into the toilet, that he caught it next time it came in the house, stuck it in the car, drove 20 miles and released it in the middle of a housing estate.
That might expalin why you have cat that doesn't seem to have gone missing locally.
I'm not advocating the aquantances actions, but I can understand how he got to that point.
Personally, I'd have trapped the owner at the same time as the cat and fly tipped them together as it wasn't really the cat's fault.