Trying to remember either the author or a title of a relatively recent series (within last 3-4 years); contemporary fantasy, set in a present-day vacation town in Wisconsin (I think), where the supernatural/paranormal is known, and in fact a tourist attraction.

There's a young attractive heroine who is charged with being the local "cop" of the local supernatural community....there's an element of romance, but I would not call it a romance series.

The young heroine answers to an ancient sort-of sea creature who can transform herself to attractive human form....

The answer came in another thread---it's the "Agents of Hel" series by Jacqueline Carey---the same author who did all the Kushiel books, but a very different series.