Amsterdam police chief, Pieter-Jaap Aalsberberg, says that grenades can be bought on the black market or dark web for 5-20 Euro. Those found in Amsterdam regularly come from Yugoslavia or Russia.
A rough estimate by the University of Utrecht is that in the Netherlands 16 billion euro are white washed per year. The study was done on behalf of the Center for Scientific Research and Documentation (WODC). About 90% of the money comes from drug trade and fraud. The researchers say that this is in particular worrying because fraud is increasing in many ways.