6 year old

My fiancé has a 6 yr old, who had told her mother that he had hit me. I'm at a lost for words, because now the mother refuses to allow lo to come over. I love her to death and has been in her life for 4 years now, we are not physical in any way nor does he spanks her. My fiancé has never put his hands on me nor have we even have any arguments around our kids. We have xfinity security and have a camera in our living room that records  our every move. How should I confront the mother? We gone through the recording and only seen us trying on our ninja Halloween costumes and my fiancé was just being silly and running around the house mimicking what ninjas do. My fiancé is a cop, I know some say just cause he's a cop doesn't mean he won't hit me. I don't wanna be the one to call their daughter a liar but I just don't get where she would think her father would hit me..and of course we'll be in court for this matter