Have to send dog back to breed...need help writing an email?

Sorry, I'm not experienced with all of this, but I would write her and let her know exactly what is happening. I find it strange she had no idea before hand about these displays of aggression, especially since he was a free dog.. If it were me, I would let her know what happened and the circumstances that you witnessed surrounding each bite. It is my belief that she needs to be aware of this. Human aggression is not okay, even in a little dog.