Missing Dog

My sister wouldn’t let me take my dog with me and since I was moving into an apartment and he’d basically been a “family dog” all of his life I figured he’d be at his happiest there. My mom got a new puppy a few months ago and had been using an invisible fence on all of the dogs we’ve ever had since I was 5 years old. It’s always worked until this new puppy. He chews at my dogs collar and runs off. My dog follows him everywhere and last night my moms dog came home tore up covered in blood. He’s getting stitches right now and my dog is still missing. He wouldn’t have left my moms dog. How can I find a dog I’m assuming can’t walk?