Father says he held daughter prisoner for nearly 24 years , fathered 7 children NEW : Mother say that Fritzl forced her to write letter saying she had run away . The daughter , now missing , has been missing since 1984 , when she was 18 , children fathered by Fritzl imprisoned with her had never seen him .
Father says he held daughter prisoner for nearly 24 years , fathered 7 children NEW : Police say Josef Fritzl forced her to write letter saying she had run away . The daughter , now 42 , has been missing since 1984 , when she was 18 Three children fathered by Fritzl imprisoned with daughter had never seen daylight .