I'd be super cautious with someone attempting to claim a dog with visible wounds. Ask for proof of ownership & permission to contact the family vet for verification. The wounds could be from a scuffle while on the loose. But it's important to make sure she's not being returned to a harmful situation.
The beautiful dog. Thank you for helping. Hopefully you will be able to keep the dog until the owner is found. Of course reported to the shelters is found and make sure whether it has a microchip or not. Thank you for keeping the baby safe