So sorry for your loss and the grim discovery makes it even more traumatic. Our cat is an indoor cat. We debated the concept of making her indoor/outdoor but in the end we decided the perils are too great to let her outdoors. We try to be imaginative in creating virtual scenarios with toy mice and squiggly things for her to play out her predatory fantasies. Kinda like the way I play my guitar in the garage to the imaginary crowd.