The Nazi officer who seized Anne Frank from her hiding place in an Amsterdam attic and deported her to a concentration camp later served in the West German intelligence agency BND, according to a new book.

In Double Agents Unmasked, journalist Peter Ferdinand-Koch revealed several cases of former SS officials taking post-war positions in the BND. He said that the man who captured the teenage Jewish diarist and her family on August 4 1944, Karl Josef Silberbauer, was one of them.

Anne, who was 15 at the time, died, along with her older sister Margo, in Bergen-Belsen just two months before the camps were liberated. Her diary was published in 1950.

Silberhauer's work after the Holocaust included undercover operations in Nazi groups and spying on communists. He was later tracked down by Simon Wiesenthal and according to Mr Ferdinand-Koch's research told the Nazi-hunter: "Why pick on me after all these years? I only did my duty."

Suspended during Wiesenthal's investigation, he was soon reinstated in his job. He died in 1971.

Mr Ferdinand-Koch's book included Silberhauer's reaction to reading Anne's diary.

He was quoted as saying: "I bought the little book last week to see if I am in it. But I am not. Maybe I should have picked it up off the floor."