You Know Who — Nicolas Freeling

An Irish diplomat is dead of a shotgun blast. Henri Castang, a French detective in exile, is obsessed with his friend's death, and with his friend's lover. From the land of Joyce and Yeats to the Italian Alps, Castang follows his obsession through a valley of desire and into a forest of latter-day European criminality, prostitution, art smuggling, and suspected IRA activity. Then a sniper's rifle wakes the good inspector from his contemplative reverie. The message is unmistakable: All along Castang has been in a ferocious battle for his life...