I'm not sure what you want to happen here. An arrest is a (temporary) suspension of a person's civil liberties. There has to be a legitimate reason under the la

I'm not sure what you want to happen here. An arrest is a (temporary) suspension of a person's civil liberties. There has to be a legitimate reason under the laws of the jurisdiction to do it. I don't know the law in England, but in the USA, if the investigating officer does not have evidence for a crime (the act, and "mens rea") or you aren't deemed a potential flight risk because you have some relation as a person of interest to someone who does in an ongoing investigation, you aren't arrested. You can be detained (which is technically what happened here - she was not free to run away from the officer while being asked the questions). She cooperated, and the questions were answered to the officer's satisfaction. Once his superiors read the report, if they find his work on scene to have been sloppy and her actions or answers suspect, they can go back and arrest her if there's cause.