The suspicion of such a link existed and has been officially investigated but never proven. Also worth noting that despite intense police investigations (still ongoing) not a single person was able to be charged for these heinous crimes which ripped apart and ruined families for no reason. The public consensus is that (a part of) the police/gendarmes/government/state security apparatus back then was involved and probably still is given the borderline comical incompetency making any official progress in the investigation. If I'm not mistaken, the investigation will be dropped in 2025 if no new elements come to light.
https://bendevannijvel.com/ contains interesting information and works well with Google translate.