Dog tells on Cat for Breaking a Salt Shaker

Our Doberman Pinscher is named Kruz. He has become the hall monitor of sorts for our cats. He doesn't allow them to scratch the furniture or be fight each other. Today our lazy cat decided to stretch out and knock a Salt Shaker to the floor. Our Doberman immediately alerted me to the destruction. He takes his role very seriously. He never harms the cats, but will bark at them. Lately the cats have become immune to his bark and are learning that he will not hurt them, so he comes to get me for help controlling them.