Can I sue my roommate for causing my dog's injury?

My dog was hit by a truck when my roommate took it out to the yard without my permission. I was not at home during that time. I received my roommate's text message telling me that I have to go home immediately because my dog involved in an accident. She told me that she took my dog out without leash, along with her own dogs. Her dogs ran across the road suddenly, and she immediately attempted to get her dogs back. The road was in heavy traffic. My dog followed her in the whole process. Unfortunately it was hit by a truck when it was crossing the road. The truck just hit and ran after the incidence. I would like to know what is the chance of winning if I sue my roommate to claim the medical bill amount back for my dog. Besides, can I make a claim for mental damage compensation? By the way, my roommate insisted that she's not responsible for any of this.