I do not believe that any animal ever deserves be subjected to the cruel and inhumane treatment some people inflict on them. The harsh reality is that people can justify just about anything they do at least to themselves. These psychopaths are all around us.
Some cat owners are a particular breed of crazy in their own right. Under the guise of allowing a cat to be a cat, these family pets are turned loose on the neighborhood and nature daily. Big cats in the wild and the domestic cat curled up snoozing on the window sill are considered "thrill killers". They of course are predators that will kill to eat but they are just as likely to kill other animals just for the thrill of the hunt, sometimes depositing these trophies at the door for their owners to find and appreciate.
Some people don't particularly like dogs. Others, don't like cats, snakes, rats whatever someone else may considered a loved pet and family member. Unlike in some countries where beloved pets are treated to spa days, professional coiffures and owners may be inclined to spends thousands of dollars on medical treatments for their much adored animal companion(s), here in the DR and elsewhere this reverence for animals in general is not shared.
Those who place a higher value on birds, frogs, lizards or other creatures in general, that are minding their own business may not view someone else's feline stalking around killing everything that moves very favorably. If you allow your pet to wander the neighborhood there is a very good chance that one day it won't come home. It is a sad commentary for sure, but just the reality. Wandering pets gets run over by vehicles, shot, poisoned and whacked with machetes. Sometimes for cause but not always.
Clearly CB's pet crossed paths with one of these callous people. Neither pellet rifles or regular rifles are legal here. We already know that doesn't stop some from possessing and using them. Whether this unfortunate animal's demise was caused by a particular type of firearm is really not all that consequential. Certainly it would be nice to know how and why for piece of mind but the takeaway here is not how or why but the fact that some psycho had the opportunity to do what they did. There will be no way to track the bullet/pellet. By talking to others CB may be successful in getting a good idea who could be responsible, but proof will be hard to come by.
Those who are inclined to harm animals tend to re-offend with increasing frequency the more they do it and get away with it. If in fact this poor cat was on the receiving end of human cruelty, the only course of action that will minimize the chances of another pet at the CB household suffering at the hands of this "neighbor" is to keep the pets at home going forward. Shooting someone's pet is pretty rare but not unheard of. The preferred method seems to be poison. Someone who shoots a cat has probably poisoned many more before advancing to direct fire. All it takes is some rat poison or a couple of over the counter pain meds mixed into a small can of food to set a trap that most wandering pets would not be able to pass by.
Sorry for your loss CB. Mark my words though, it will happen again if you allow the circumstances to repeat. Good luck CB, hope you get some closure if not outright justice. It's up to you to keep the your other pets safe.