A Stroke of Midnight

A Stroke of Midnight is the fourth book in the Merry Gentry series by Laurell K. Hamilton.

Plot
Solving a double homicide, avoiding assassins, and coping with growing, sometimes uncontrollable, power keep Princess Meredith NicEssus (aka Meredith Gentry) busy.

When someone murders a fey and a human reporter during a press conference inside the Unseelie mound, Merry calls in the human police to assist (and inadvertently involves the FBI as well).

But once on magical turf, human police face challenges and dangers of which the princess was unaware. The Unseelie court seems to be tiring of  Andais, the Queen of Air and Darkness. The queen's son and Merry's rival for the throne, Prince Cel, looms as a corrupt menace to her future.