BRUSSELS (AFP) - He was dubbed the "monster of Charleroi" by the Belgian press but psychiatrists say Marc Dutroux is less a paedophile than an icy-hearted predator with a murderous desire to control his victims.

Dutroux, 56, asked a special court for early release on Monday after serving almost 16 years of a life sentence for the kidnap, rape and gruesome murder of several young girls, crimes that shocked Belgium and the world in 1996.

Four of the girls, including two eight-year-olds, were found dead. Two others were rescued from the cellar of a property belonging to the former electrician near the southern Belgian town of Charleroi.

The public shock turned to fury when it emerged not only that police had missed a string of clues that could have led to Dutroux being apprehended earlier but that he had been released from jail in 1992 after serving just three years of a 13-year sentence for the abduction and rape of five girls.

According to a report issued by a panel of psychiatrists who analysed him after his arrest in August 1996, Dutroux does not fit the classic profile of a paedophile.

Two of his female victims, whose bodies were unearthed a fortnight after his arrest, were aged 17 and 19 when they disappeared the year before.

"The age of the victims did not seem to arouse in him any given effect or to play a particular role, beyond allowing him to kidnap them, to manipulate them, to confine them," the experts wrote.

Sabine Dardenne, who was 12 when she was rescued from the Charleroi cellar, described how Dutroux managed to persuade her that he was protecting her from a gang that was out to kill her.

According to testimony heard during the trial, Dardenne and Laetitia Delhez (then 14) embraced their torturer when police entered the dungeon, terrified that their rescuers were members of the gang.

What produced this "monster"? There are clues in his troubled upbringing but no clear explanation for Dutroux's descent into a career of rape and murder that cast him as Belgium's most hated man.

He was born on Nov 6, 1956, in Brussels, the eldest of five children, to teacher parents who he says frequently beat him. But there is no suggestion of sexual abuse.

After his parents split up in 1971, Dutroux left home and became a drifter.

At the age of 18, he married for the first time.

That woman and a string of mistresses that Dutroux picked up describe him as a charmer but also a manipulator with a propensity to control weaker-willed people.

One of his mistresses was Michelle Martin, who later became his second wife. She was among three co-defendants who were jailed alongside Dutroux, last year winning parole on condition of moving into a remote convent.

In 1979, Dutroux received the first of a series of convictions for theft, violent muggings, drug-dealing and trading in stolen cars - a lucrative activity that is said to have helped him amass at least seven houses.

In 1986 Dutroux and Michelle Martin were arrested for the abduction and rape of five girls, which led to the lengthy jail term he received in 1989.

Released in 1992 under a government scheme that was supposed to keep a close eye on sexual offenders in the community, Dutroux did not register again on official radars until four years later.

By that time, four girls and an accomplice were dead, and another two girls had suffered an ordeal that will scar them for life.