Mossad attempted to capture Mengele in the same raid that captured Eichmann but Mengele, somehow, was a step ahead of them and fled to non-extradition treaty Paraguy before they ever arrived. He later moved to Brazil and lived under an assumed name and died of a stroke that he had while swimming. Never served a day in jail or even stood trial for his crimes. Records show that he actually helped kill a girl while performing an illegal abortion, too. The abortions no doubt padded his wallet and made it possible for him to live a comfortable expatriate life in Brazil and Paraguay.
Doubtful Mengele escaped final judgement even though he escaped earthly judgement.