I think even with bruises, if the parent says they were disciplining the child, the police will just document it and close out the file.
But the question is about historical incidents of other household members. As in, x years ago, police was called a few times because these people were having a fist fight in front of the children. For the last x years, these people have not been around children. Now someone is proposing to have a child is love with them. Does the court only look at the child’s parent? Or are the other household members relevant?