Professor Jeremy Coid, professor of forensic psychiatry at Queen Mary College, University of London, considers why Josef Fritzl may have changed his plea.
Josef Fritzl covered his face in front of the media
I think there are two things going on here: this is a man who is very private; and he has to be in control.
While Fritzl might like to say he changed his plea after hearing his daughter's emotional evidence - that for the first time he was able to understand his daughter's feelings - from what I know of similar offenders, I would be extremely sceptical.
When the trial started, I'm sure Fritzl believed he was going to use his day in court to deny some of the charges and to portray himself as a good father, who was not as bad as people might think.
But, he is obviously socially avoidant and anxious in social situations. In court, he was confronted by the reality of the situation. He was no longer in control - facing the court and the media's flashbulbs would have been unbearable for him.
We saw him covering his face - this was not just to hide from the media but because it was painful for him to be exposed.
I have seen this before with this type of offender.
A confession allowed this whole process to stop. We shouldn't see this as an admission of remorse.
Among incest offenders, Fritzl is down the heavy duty end - a sadist who is intensely perverted.
Offending in the way he did would have made him feel grandiose. Raping his daughter and acting out his perversions would have given him sadistic pleasure.
To me it was interesting that he [acted out his perversions] within his own home. He has previously been convicted of a sexual offence. My hunch is that he wasn't any good at offending outside the home.
He was not out stalking the alleyways. But, because of his personality structure, it all turned inwards to the family.
This socially avoidant part of his personality would have caused him to withdraw from the trial.
Professor Jeremy Coid, who specialises in the area of serious violence including sexual violence, was interviewed by Kathryn Westcott.