Does anyone know Domestic Violence laws in NC?

Are the police required to go into a house to check if they are called? Can they just be reassured at the door and sent on their way?

Also,if the police accompanied a father to pick up a daughter at a home because she could not get away and the girl had injuries on her, would the police not be required to make an arrest?

and hung up.

The police showed up (I hadn't known it happened) and I answered the door but didn't let them in. He asked if someone called 911 and I said no. He said 'are you sure everything's all right' and I said yes.

He then left.

I know the police went to get this girl with her father and that she has injuries ( bruised back and a badly bitten thumb) after she managed to call her mother to say she wanted to come home but couldn't get away from them (a young husband and wife, apparently some sort of threeway relationship). I am just confused because I would have thought they would arrest someone. Instead the girl is safely away and is filing a restraining order in another state to keep him away. I was also told the police were called by someone and went to the house last week but the husband said nothing was wrong and the police just left. the abused girl was told to keep quite in another room when they were at the door. I would have thought the police would go check. Now another girl has taken her place.....sigh

I am in Massachusetts so I don't know how the laws are in regards to this down there.

Officer B may have no idea Officer A was out there last week.