Former tenant: Fritzl's son also went into cellar

AMSTETTEN, Austria (CNN) - A man who previously rented an apartment from a now-73-year-old man accused of holding his daughter captive in his cellar for 24 years told CNN Thursday he saw the man's son enter the basement.

Alfred Dubanowsky said he rented a ground-floor apartment at Josef Fritzl's home from 1995 through 2007. He said there was a verbal agreement between Fritzl and the house's tenants that they were not to enter the cellar or the garden or photograph the premises or they would be kicked out.

Police said Fritzl confessed to keeping his daughter Elisabeth in the basement for more than two decades, where he repeatedly raped her and fathered seven children with her - six of whom survived.

Dubanowsky said he saw Fritzl's son, also named Josef Fritzl, enter the cellar. He also saw the elder Fritzl enter the basement frequently at night.