Chasm City By Alastair Reynolds

The once-utopian Chasm City—a doomed human settlement on an otherwise inhospitable planet—has been overrun by a virus known as the Melding Plague, capable of infecting any body, organic or computerized. Now, with the entire city corrupted—from the people to the very buildings they inhabit—only the most wretched sort of existence remains. For security operative Tanner Mirabel, it is the landscape of nightmares through which he searches for a low-life postmortal killer. But the stakes are raised when his search brings him face to face with a centuries-old atrocity that history would rather forget.