Finally. in 1957 Soviet authorities acknowledged that Wallenberg had been taken prisoner in 1945. but they claimed that he died of a heart attack while in a Soviet prison in 1947. More recent reports from within the Soviet Union. however. indicate that Wallenberg might still have been alive as recently as a few years ago. In 1975 a Soviet Jew named Jan Kaplan was arrested on charges of black marketeering shortly after applying for an exit visa to Israel. When he was freed 18 months later for health reasons. he called his daughter in Israel. and in the course of the conversation he mentioned a Swede he had met in prison who had been held by the Russians for some 30 years. Kaplan was then rearrested. and his daughter heard nothing further until July 1979. when her mother smuggled out a letter explaining that Kaplan had been rearrested because he had mentioned "a Swiss or Swede named Wallberg" whom he had met in the prison infirmary.