On the basis of a case study, this article examines how, during the Second World War, the Brussels Prosecution Service dealt with the problem of the division of competencies and exchange of information with the occupier in the case of politically motivated attacks on collaborators. During the first years of the occupation, the politics of the lesser evil was prevalent among the magistrates. In this context, official reports and other information from judicial investigations were increasingly being transmitted to the German police services. When in 1942 violence against collaborators intensified, the Belgian judiciary agreed to the prosecution of the perpetrators, on condition that the occupier respected judicial autonomy. The investigation of a group of young persons, led by Eugene Predom, who threatened collaborators thus became a test case. When a few months later Predom was executed as a hostage during a reprisal attack, it became clear that the occupation authorities had no intention of always leaving the trial of persons arrested by the Belgian police to the Belgian justice. Due in part to reports in the clandestine press, Predom's death led to agitation among the judiciary, who realized that the division of competencies and information exchange made them potentially guilty of denunciation of civilians. As a result, the General Prosecutor of Brussels decided after due consideration to suspend all law enforcement tasks. After the liberation, the Office of the Chief Military Prosecutor started an investigation of the case Predom. This ultimately resulted in a dismissal because it could not be proven that the judges and police officers involved had acted with malicious intent. Especially during the 1940s, the communists used the case Predom in their attack on the politics of the lesser evil pursued by the judiciary during the occupation.