Sitter Hit my dog

So my dog was dropped off at a sitters house a few days ago, and since this is a new sitter that I don’t know very well, I decided that for my comfort and peace of mind, I would put an audio listening device in my dogs belongings. I’m so glad my intuition told me to do this because while listening back on the recordings the device took, I heard what sounded like a hard hit, and then my dog crying right after. This was undoubtedly the sound of my sitter hitting my dog. I am literally shaking as I type this because I really don’t know what to do. to make matters worse, I continued listening and the sitter says (presumably to my dog) “I’m sorry I smacked you on the butt”. My dogs booking ends tomorrow but I honestly don’t want to keep him there another night bc I am just so afraid of what else she might do to him. Do I call the police? I was doing some googling and apparently in my state it’s illegal to record someone without their consent, so I’m worried I might turn in the recording as evidence and instead I will be getting in trouble. I wish I had someone to call that could pick up my baby for me, he’s probably so scared right now and just thinking about that hurts me, I don’t think I’ll ever be able to leave him with another stranger again. Any advice is appreciated