According to the press, he is said to have forced his daughter to dig out the cellar by hand:
http://www.dailymail.co.uk/pages/live/arti...e#StartComments
Still other accounts mention him building the cellar to code, even applying for a building permit.
Pictures of the the 'dungeon' reveal that it was indeed built to code, and is beautifully paneled from floor to walls to ceiling.

Then we are told that the daughter of this monster 'disappeared' at age 18, and no one, including her own mother, ever thought
of looking in the basement that was completed with a building permit. Oh, he built it in secret, which meant he somehow managed
to get floor tiles, paneling , plumbing fixtures , furniture, etc. etc. down there without his wife ever knowing, and no one hearing
the sawing, hammering , etc. etc. What a pile of b.s.
HE even expanded it a couple of times after his daughter went missing, but his pure and perfect wife never once suspected that
something linked to her daughter's disappearance might be going on. He spent hours down there, and managed to feed
and clothe two or three people for 1/4 century without wifey ever wondering what is going on. Then there is the matter of
their raising two of his and his daughter's inbred children upstairs in the house, with 'normal lives'. What did wifey do when
Josef showed up from the basement every couple of years with a couple of extra babies? Hey, honey, look what I found. LEts keep em!
None of this b.s. story makes sense.
