Several hundred people demonstrated in Brussels on Sunday against any early release for notorious child-killer Marc Dutroux, days after prosecutors considered his case.
The convicted paedophile and murderer, who turns 63 in November, was given a life sentence in 2004 for abducting and raping six girls in 1995-96 and for the deaths of four of them.
But on Thursday, prosecutors approved a request for a new psychiatric assessment of Dutroux, which could open the way for his conditional release.
Around 400 people, according to a police estimate, turned out in the rain after a call on social media to stage a "Black March", the colour of mourning. Many of the marchers were parents with children.
Dutroux murdered two of his victims and two died of hunger in a dungeon he kept in the basement of his home.
Dutroux's mental health has not been assessed since his appearance before a court 15 years ago when he was described as a "real psychopath", a "perverted narcissist" and a "manipulator".
Dutroux's lawyer Bruno Dayez, who took up the case in 2016, started moves for a re-evaluation of his mental state in the hope of obtaining his conditional release in 2021, when Dutroux would have served 25 years in prison.
Dayez said three medical experts could be designated to examine Dutroux. Five judges will deliver their ruling on October 28 in Brussels.
"I don't think rapists get better," one demonstrator told Belgian broadcaster RTL-TVI.
"I think they start again and that, if they reoffend, we are all responsible for having let someone out," she added.
In Belgium, prisoners who are jailed for 30 years rarely get early release. The five judges must approve it unanimously and their ruling is subject to appeal.