The person(s) responsible is having fun, but their good times will not be stopped with cruelty to dogs. They’ll need a bigger thrill and escalate to obscenely abusing a child.
No doubt, they’ve shared their deeds with friends or family, who are too scared or too shocked to report. The way to stop him/her/them is to raise money that will loosen the tongues of those in the know. Then the predators will be brought to justice and the innocent will no longer be their playthings.