The Boys from Brazil by Ira Levin 

Mengele is alive and well in South America and he’s been busy.  There is a plan afoot to create the fourth Reich.  But someone found him and recorded a secret dinner meeting wherein he has assigned 94 names of older men he needs killed in order for his plan to go forward.  These men must be around 65, have a much younger wife, and a teenage son.  The must be killed in a specific order and on or near specific dates.  Just as the recorder has managed to get a famous Nazi hunter, Yakov Liberman, on the phone, but before he can relay the details, Mengele and his men burst into the hotel room and kill the young man.  Yakov can’t get it off his mind and asks a reporter friend to let him know about men fitting the description dying, either in suspicious accidents or outright murder.  The clippings start coming in with far more volume that Liberman expected.  He poses a hypothetical question while giving a lecture at a university.  This leads him to talking to a geneticist.  The conclusion involves a pattern that matches the growth of the most evil man in history.  It seems that Mengele, using some of Hitler’s hair, has created 94 clones and had them delivered to families that were turned down because of the difference in the age of the father and the mother.  When Hitler was a teenager, his father was killed.  Mengele has 94 chances to create a new Hitler from the boys from Brazil.