She met him at school in 1940, his family also having fled from Germany to Amsterdam the previous year. At age 11, Anne fell in love with Schiff and later, while in hiding in Amsterdam herself, wrote about how much she missed him.
Her last mention of Schiff was in 1944, the year her family's safe house was raided by the German security police. She later died in a Nazi prison camp.
Sunday's The Observer newspaper reported that Ernst Michaelis, 81, of London, found a photo of Schiff in a family collection after realizing that Anne Frank was writing about a boy he had known as a fellow student in Berlin.
Michaelis, who moved from Germany to Britain many years ago, said he has had the photo authenticated and that it will be displayed on the Anne Frank House Web site.
Schiff also is believed to have died in a Nazi prison camp.
The Anne Frank Foundation in the Netherlands was closed on Sunday and could not immediately be reached by The Associated Press for comment.