London, May 3 : Cellar dad Josef Fritzl wants to plead insanity to explain his sick crimes, it has emerged.
The sex beast has told his lawyer: "I don't think I'm all there."
The rapist has also begged legal ace Rudolf Mayer to arrange psychological tests to prove he is mentally unfit.
"Josef has said, 'I need to know what is at the root of me - I knew I was different and something was not right with me'," The Sun quoted Mayer, as saying.
Mayer added: "In the court case it will certainly be a question of whether he was legally sane at the alleged time of the crime."
The brief said he would be looking back at Fritzl's background to try to find evidence of "a psychological condition".
Mayer also revealed that warped Fritzl has begged both his families to visit him in jail.
Mayer said: "He has had no visitors yet but has told me he'd be delighted if they came."