Step child bullying/manipulative behaviour
We have a mix of children but my bio daughter is 8 and have a step who is same age. They have what we expect in terms of relationship, nice positive fun times and minor squabbles which pass. SKs mum engages in PA and this has a knock on effect. Last week she's ramped up my daughter is a bad influence on her and she doesn't want her around her anymore. Fiancé and I have a near 2 year old child together....
we have checked through SDs mobile which is now gone and there are some concerning videos (for me at least). She is recording my daughter happily playing and calls her a "f*ing cow" has her saves as "cow" and a photo of a cow and then another video in which she's kicking her off a bed in our home telling her to move and my daughter is just not reacting ignoring her. SD is very emotionally manipulative, tends to pinch and hit and then puts on baby voice to dad and cries and says she wants to go home. Used to break all my jewellery etc.
As an adult I can deal with this but concerned for my daughter in this position in her own home and safe space. She hasn't even mentioned it to me but I suspected as much as I've watched the comments under her breath and deliberate nastiness from SD on occasion.
How should this be approached? I tried to talk to OH and he was quite blasé "she's a little sod" etc but that's it