A Quiet Flame: Philip Kerr

Posing as an escaping Nazi war-criminal Bernie Gunther arrives in Buenos Aires and, having revealed his real identity to the local chief of police, discovers that his reputation as a detective goes before him.
A young girl has been murdered in peculiarly gruesome circumstances that strongly resemble Bernie's final case as a homicide detective with the Berlin police. A case he had failed to solve.
Circumstances lead the chief of police in Buenos Aires to suppose that the murderer may be one of several thousand ex Nazis who have fetched up in Argentina since 1945. And, therefore, who better than Bernie Gunther to help him track that murderer down?