The lawyer of the Austrian man who held his daughter captive and fathered her seven children said on the day before his client was ?emotionally a broken man?.

Lawyer Rudolf Mayer told Reuters Television that it would be hard for Josef Fritzl to get a fair trial in front of a jury because of the massive publicity generated by the case.

Fritzl, 73, has admitted keeping his daughter Elisabeth in a cellar for 24 years. Three of her children had spent their entire lives underground until the case was uncovered just over a week ago.

Mayer said Fritzl should have psychiatric tests to evaluate whether he was fit to stand trial.

?There must be some (psychiatric) disturbance otherwise no one would commit such acts. So is this disturbance so great that he is not of sound mind, not responsible for the acts he has committed?? Mayer said.

Prosecutors are investigating Fritzl for rape, incest, coercion and the death of one of the children, a baby whose remains he burned in a furnace.

The case has generated headlines worldwide and prompted questions about how the abuse in the small town of Amstetten went undetected for so long.

Mayer said this could influence jurors. ?The problem is that lay jurors, naturally, do not bring the objectivity and lack of prejudice to the trial that professional judges always bring.?

Rape Conviction

Mayer acknowledged reports that his client had a rape conviction from the 1960s, around the time Elisabeth, who is 42, was born. ?Such a conviction is not in the files at present but ... it is true that it has been found in the archives.?

The newspaper Oberoesterreichische Nachrichten has reproduced what it said was a 1967 court record from state archives in the city of Linz, in which a Josef F. was accused of breaking into the apartment of a 24-year-old nurse and raping her.

Josef Fritzl?s sister-in-law, identified as Christine R., told the daily Oesterreich that he had gone to jail for the offence. ?I was 16 when he was locked up for rape,? she said.

In a video interview aired by a number of news channels, she said she believed Fritzl had spent a year and a half in jail, and that his wife Rosemarie, despite her shock, had tried to hold the family together.

Austrian officials will say only that, if Fritzl had such a rape conviction, it would have been purged from the records after 15 years at the latest.

Authorities have said officials followed correct procedures in allowing Fritzl and his wife, who had seven grown-up children of their own, to care for three of the children he had with his daughter, ostensibly after she abandoned them on their doorstep.

Elisabeth was kept imprisoned in a cellar complex beneath the family?s grey apartment block with her three other surviving children ? a daughter, now 19, and two sons aged 18 and 5.

Detectives working in the bunker are able to work for only an hour at a time because of the foul air.

Elisabeth and her surviving children are all being cared for in hospital. Doctors say the eldest daughter ? who Fritzl took to hospital from the cellar two weeks ago ? remains critically ill but stable. They have not given a detailed diagnosis.

Fritzl is being held in a cell in the Lower Austria provincial capital of St Poelten.