BERLIN (AP) – Three siblings who claim they are Charles Lindbergh’s out-of-wedlock children are releasing a book next week that alleges the famous flier had seven illegitimate children in all from relationships with their mother, her sister and his German private secretary.

“The Double Life of Charles A. Lindbergh” alleges that Lindbergh had three children with Munich hatmaker Brigitte Hesshaimer, two children with her sister Marietta, and another two children with his German private secretary, identified only as Valeska, the publishing company said.

Brigitte Hesshaimer’s children, Dyrk and David Hesshaimer and Astrid Bouteuil, said in 2003 a DNA test proved they were the U.S. aviator’s children, adding that they had met their American half-siblings in the United States.

They also offered as evidence a bundle of 112 letters they said Lindbergh wrote to their mother.

The book, written by the Munich author Rudolf Schroeck with the three, contains no new evidence of Lindbergh’s paternity.

“It’s fact, we don’t have to prove it.” Anton Schwenk, an attorney and the siblings’ spokesman, said in a telephone interview.

The Hesshaimers’ mother is now dead. Both the other women alleged to have had affairs with Lindbergh are still alive, but were not interviewed for the book, Schwenk said.

A Marietta Hesshaimer believed to be the woman referred to in the book did not answer her telephone in Switzerland. It was not known where Valeska could be contacted.

Kelley Welf, spokeswoman for The Charles A. and Anne Morrow Lindbergh Foundation in Minnesota, said that she could not comment on the allegations but would pass a request along to the family. They did not immediately respond.

When the Hesshaimers’ claim that they were Lindbergh’s children was first made public in 2003, the Lindbergh family in the United States acknowledged it, but issued a statement saying they did not want to comment further because “it is clearly a private and personal issue which we feel is inappropriate to explore through the media.”

Lindbergh’s 1927 solo flight across the Atlantic made him a global celebrity. He married Anne Morrow in 1929, and they had six children. In 1932, their first-born baby son was kidnapped and murdered.

The marriage endured until Lindbergh’s death in 1974, but during the last decades of his life he roamed the globe, rarely visiting his Connecticut home. Anne Morrow Lindbergh died in 2001, the same year as Brigitte Hesshaimer.

The publisher Heyne Verlag, a division of Random House, said the book will be in stores Monday. A spokeswoman had no information on whether an English release was planned.