I will be dead wrong if the bf or the mother isn't arrested and charged in this case. There have been too many cases like this scenario. I think the stats might lean toward a bf who single mothers allow to move in, and then ignore the resentment and abuse their child experiences from the bf. These types of single mothers are desperate for a man who they think will love them and will support them. They put him, and their needs ahead of their poor kid who is deemed as baggage in the their relationship.
It is possible that mom caved to the bf's resentment of Maliyah being in their lives, or his constant criticism of her behavior? She could have lashed out in a rage toward Maliyah, but if she was a half decent mother who cared about her daughter, I can't see that happening. Maybe she was the abuser and the bf is protecting her.
LE are to them, and I expect an arrest(s) in the near future. jmo