A Coffin for Dimitrios by Eric Ambler (1937) Alfred A. Knopf

A classic detective story about a man who wears many names.  He is wanted for the murder of a Jewish money lender, an attempted assassination of a Prime Minister, various robberies, drug smuggling, even the betrayal of his own criminal gang.  A British writer of detective stories becomes friends with Turkish commander of secret police who shows him the body of the notorious Dimitrios.  The writer, Latimer, wonders if such a man’s activities can be traced backwards, as an academic exercise to see how his own story plots match with reality.  This quest takes him from Istanbul to Athens, to Bucharest, Geneva, and Paris.  People help, but people are suspicious of the motives of a man looking into such a criminal.  During his quest, he meets one of the people Dimitrios betrayed and is caught-up in a blackmail scheme.  Will he survive?  Was the corpse he saw really Dimitrios?  If not, will Latimer become the next victim in this sordid tale?