The Prefect — Alastair Reynolds

Tom Dreyfus is a Prefect, a law-enforcement officer with, the Panoply. His beat is the Glitter Band, that vast swirl of space habitats orbiting the planet Yellowstone, the teeming hub of a human interstellar empire spanning many worlds.

His current case: investigating a murderous attack against one of the habitats that left over nine hundred people dead. But his investigation uncovers something far more serious than mass slaughter -- a covert plot by an enigmatic entity who seeks nothing less than total control of the Glitter Band.