Self's deception - Bernhard Schlink

In Self's Deception, private investigator Gerhard Self receives a request to track down the daughter of Herr Salger, the Assistant Secretary of Bonn, who's been absent from her translation classes at the university. Repelled by the pomposity of the government official, he rejects the case. But an insistent letter--and five thousand marks--changes his mind. After discreet interrogations at her school and her former residences, and a quick survey of the local hospitals, it turns out she washed up at a psych ward where he's told she had fallen out of a window earlier that week and died. Self suspects that this may be a lie, and soon decides that one of the doctors is covering for her. As his investigation takes a sinister turn he realises that his quarry may have been involved in a terrorist incident--but a terrorist incident that the government seems intent on covering up.
With the woman still missing, and a growing suspicion that the client who hired him may not actually be Herr Salger at all, Self finds himself embroiled in a dark and complex conspiracy that reaches to the very top of government.
But with his plentiful supply of Sweet Aftons, and his cat Turbo to talk to (as well as the realisation that the young lady he is searching for is not without her own charms) Self sets out on his latest adventure with his inimitable blend of cynicism and charm.