London, May 9 : Sex beast Josef Fritzl humiliated his dowdy wife at a swingers club by forcing her to watch him romp with another woman.
Paul Stocker, a builder - who tried to sell Fritzl a house - claims he saw him at the Caribik Club, near Amstetten, back in 1997.
"An elderly couple came in, they looked just like an old pair you might see in a park feeding the pigeons," the Mirror quoted Stocker, as saying.
"I was speechless when I realised it was Fritzl with his wife. She went without a word to stand in the corner.
"He treated her like a dog. She had to sit in a corner and watch as he did stuff with a young woman."
Stocker also told how Fritzl bragged about using Viagra to boost his sex life.