A Philosophical Investigation - Philip Kerr

London, 2013, and the city is battling an epidemic of serial killings - even with the widespread government use of DNA detection, brain-imaging, and the ''punitive coma''. Detective Isadora ''Jake'' Jacowicz is hunting a murderer, code-named ''Wittgenstein,'' who has taken it upon himself to eliminate anyone who has tested positive for a tendency towards violent behaviour - even if they''ve never committed a crime. His intellectual brilliance is matched only by his homicidal madness.