Some people are very weird about dogs and cats. My wife's neighbor used to leave dog droppings on her car because she had a dog. Now the dog never went into his yard because she wouldn't let him off his leash on a runner in the backyard. But he was convinced that every dog dropping must have come from that dog.
She threw them onto his porch and he eventually caught a clue.
Note:People who are cruel to animals are almost always dangerous to humans.