Even for Belgians it's hard to grasp.  You should understand the backdrop against which all of this happened:  2 police forces who were essentially at each others' throat, economic crisis and drug trade that took off and was countered by the introduction of 'American' crime fighting strategies for which no legal framework existed in Belgium.

The result was that a number of high-profile cops became criminals or were controlled by criminals.  Coupled with almost inexistant forensics procedures  this set the scene for criminal excesses that went unpunished and were not really investigated as in many cases, criminals had some dirt on the detectives that were investigating them.