The Oblivion Trilogy by Steve P Lee

Charlestown is a settlement on the far flung frontier planet of Obsirion II, recently colonised by The British Corporation. Home primarily to engineers, scientists, and their families, it is not as technologically advanced as the planets closer to Earth and quite sleepy. Nevertheless, there is a small town police force headed up by Sergeant Mint Harris. Shockingly, a murder is reported at the town's hydrogen fuel plant and Mint is called in to investigate alongside her scenes of crime officer, Roman Reckhart. Oblivion follows Mint's investigation as it takes her in an unexpected direction and introduces her to another element of the Corporation's operation she had no idea existed. The Department 44 Files leads onwards from the thrilling end of Oblivion as Roman reviews reports on certain, previously unexplained events in the wider arena of humanity's space exploration and colonisation projects. Assault on Charlestown completes the trilogy as Roman and Mint are further embroiled in the desperate attempt to rid Obsirion II, and maybe the entire human race, of a terrible, ancient and malevolent threat.