13/04/2017 05:23 BST | Updated 13/04/2017 05:50 BST

I've Never Met Anyone As Cunning, Deceiving And Remorseless As Josef Fritzl

Ho New / Reuters

I first got to know Josef Fritzl more than a quarter of a century ago when he first reported his daughter Elisabeth as missing. And ever since he's been detached from reality, and as so many psychopaths - cunning and deceiving.

As one English criminologist once put it: walk into a prison and you'll find a lot of soft spoken, good mannered people, and yet all of them has a secret to hide. Like Josef Fritzl who of course locked his next of kin down in a dungeon and even burned one of his stillborn babies (fathered with his own daughter).

I've been in journalism for more than 30 years now and I'm considered as a veteran crime reporter, but never have I experienced this amount of horror or such an individual. He hasn't felt any remorse up to this day as far as I personally could see.

The last time I asked him about his daughter he was as cunning as he was at the first time. With just one little difference: the incest father and sexual predator seemed slightly annoyed about the question I put forward. Perhaps because his world was about to collapse. Yet he still managed to hide his secrets only hours before he was taken in by the police.

When Elisabeth broke down and revealed that some of her kids were still in the dark dark prison dug out by this monster, he just turned round to the detectives in his cell and coldly asked: "Have you found them all". Then he went to sleep again. As cold as can be! And that's how he has been reacting to this day.

Can a psychopath of his likes, be held accountable for his horrendous crimes? After dealing with that cold blooded man for so long a time, there's only one answer for me: Keep him locked up for the rest of his life. And let him suffer like he let his family suffer. Especially as he has never shown any remorse what so ever.

Fritzl: What Happened Next will be broadcast on Thursday 13th April at 10pm on Channel 5.