There are plenty of older documentaries, mostly mainstream posted on Youtube about this case. Here are a couple to view, one by an influencer, the other a mainstream media with interviews, dubbed in English.
The BELGIAN DEMON - Marc Dutroux
The Marc Dutroux Pedophile Ring: Government Officials, Murder & Satanic Sacrifices (VERY DISTURBING)
In Poland we even have the term for that “Serial suicider” though in Poland people end up dead like that usually because they have some evidence about what current politicians of PiS and PO and their business patrons did in 90’s and how they ended up rich back then.
Or evidence of what they did the year before.