AMSTERDAM — Russian archivists have published new material from a German officer imprisoned after World War II who shared a cell with Raoul Wallenberg, the missing Swedish diplomat credited with rescuing tens of thousands of Hungarian Jews.

Publication of the statements from Willy Roedel came as a surprise since the Russians had previously denied they existed, say two independent scholars who have researched the Wallenberg mystery for decades, in a paper released Monday.

That raises suspicions that Moscow may be withholding information which could help solve the 66-year-old puzzle of Wallenberg’s arrest and disappearance in the gulag, the vast Soviet network of prisons, labor camps and mental asylums, said German researcher Susanne Berger and Russian scholar Vadim Birstein, who were members of the Swedish-Russian Working Group that conducted a 10-year investigation during the 1990s....

The Russians maintain Wallenberg was executed July 17, 1947, but the Working Group said in its 2000 report there is strong evidence suggesting he lived many years as a prisoner under a different identify or known only by a number, perhaps as late as the 1980s....