Yes you can be arrested without charges being filed against you. They will be filed but they have to go down the paper work trail. Within 24 hours after your arrest, you will see a judge. They will review the facts and make a decision. They are a number of programs about this on you tube should you wish to enhance your knowledge,
Thank you. So really, the policeman was being exceptionally nice. He did not need to tell her anything, just that she is under arrest.