How was Jioseph Fritzel's celler discovered???

Question

How was Jioseph Fritzel's celler discovered???

Answer 1

One of the females he had fathered wound up in the hospital. gravely ill and in a coma. The hospital authorities then questioned the female's mother and discovered the mother was Fritzel's own daughter. They informed police authorities who raided the house and gained access to the infamous basement.

My source is the English language "Report From Austria" broadcast by Radio Austria International (via ITunes podcast) at the time the events began to unfold.