Boyfriends daughter

Natasha

My boyfriends daughter today on our way home said “ mommy hit me” out of no where and when we got home we asked her where she was hit and she said in the stomach and when we looked there was no bruises and her stomach didn’t hurt and this isn’t the first time she has days something like this. I talked to her grandparent today and he said that last week she had said our dog bite her and that my boyfriend hit my dog in the head. Which my dog didn’t do that and he didn’t hit her. My mom thinks that we should get social services involved but I’m at a loss of what to do. Her grandpa said that she was put in a time out by her mom for doing something to her toys and she got upset that she was put in a time out and hit her mom. This isn’t the first time that she has sit. She has hit kids and teachers and also her other grandparents. Any help would be greatly appreciated.