In 1957, members of the West German government provided Israel with information that Adolf Eichmann was hiding in Argentina under the name "Ricardo Klement". Eichmann, as director of Department IV-B4 of the Third Reich's Reich Main Security Office during the Second World War, had played a crucial role in the planning and execution of the so-called "Final Solution to the Jewish Question". Israeli prime minister David Ben-Gurion believed that seeking Eichmann's extradition from Argentina by legal and diplomatic methods would be unsuccessful. In 1959, he placed Harel in charge of the operation to locate, seize, and secretly extract Eichmann from Argentina, with the intention of returning him to Israel to stand trial. In April 1960, Harel's team of agents arrived in Buenos Aires, and tracked Eichmann to a residence in the San Fernando neighborhood of the city. Harel followed soon after. On May 11, they kidnapped Eichmann as he walked from a bus stop to his home. Days later, Eichmann was drugged and clandestinely placed on an Israeli diplomatic aircraft, disguised as a crew member. He was flown to Tel Aviv. According to Harel himself, when he arrived back in Israel with the captured Eichmann, Harel went to Ben-Gurion's office and told the prime minister: "I've brought you a present. Eichmann is here."