One of Belgium's most notorious men has gone on trial amid tight police security in the town of Arlon.
It has taken nearly eight years for the trial to begin
Marc Dutroux, 47, is accused of kidnapping and abusing six girls aged from eight to 19 in the 1990s, and of murdering four of them.
The case has taken eight years to come to trial, partly because police were investigating claims that Mr Dutroux was part of a wider paedophile ring.
Perceived police incompetence triggered huge demonstrations in Belgium.
Mr Dutroux, who has admitted abducting and imprisoning girls but denies murdering them, appeared in the courtroom with his co-defendants behind bullet-proof glass.
He spoke in court only briefly, to confirm his name and say he was unemployed.
He is standing trial with his estranged wife, Michelle Martin, 44, businessman Michel Nihoul, 62, and Michel Lelievre, 32, a drug addict alleged to have helped Mr Dutroux kidnap several young girls.
The first day of the trial was devoted to selecting a jury from 180 candidates. The case is expected to last three months, hear from more than 450 witnesses and cost 4.6 million euros (£3m).
Outside the courthouse, more than 200 reporters, photographers and camera crews had gathered while some shops in Arlon posted pictures of the victims in their front windows.
About 300 police guarded the court - hoping to avoid a repeat of a 1998 incident when Mr Dutroux succeeded in escaping for three hours after overpowering an officer who was guarding him.
A man who was trying to set up a gallows outside the court on Monday morning was arrested, the French AFP news agency reported.
Mr Dutroux has fuelled conspiracy theories by claiming he was "used as an instrument by others", according to a letter obtained by Belgian television station VTM on Sunday.
"People want to believe that I am at the centre of everything. They are mistaken," he said.
Thousands of Belgians took to the streets in protest
All four defendants were arrested in August 1996 by police investigating the abductions of two girls, Sabine Dardenne, then aged 12, and Laetitia Delhez, 14.
The girls were discovered alive two days later in the cellar of a property belonging to Mr Dutroux in the southern town of Charleroi.
Investigators then unearthed the bodies of four other girls who had been missing for more than a year, from the gardens of other Dutroux properties.
They also dug up the body of Bernard Weinstein, an accomplice whom Mr Dutroux has admitted murdering.
Mr Dutroux has accused the Belgian police and justice system of refusing to investigate leads he provided, which he says would prove that he was just part of a wider paedophile conspiracy.
But Belgian officials say that the long time bringing the case to court results partly from the need to investigate these alleged networks, which they say do not exist.
In 1996, hundreds of thousands of people took to the streets in the White March, one of the biggest protests Brussels has ever seen.
The government - shaken by the immense scale of public anger at perceived police incompetence - promised changes to the constitution to reduce political interference in the judicial process.