Yes i think there is a relation because of bitcoin nature as an anonymous currency usable online and offline it might have increased some online crimes like cross-continent drug dealing and with no ID's and evidence. And so some criminals had the idea of using bitcoins to use bitcoin in their crimes.
quite agree with you with its anonymous nature it can be used by criminals and can be used for criminal purpose...
it has no limit of countries or continent can be used worldwide and has wide range of users around the globe so, you can make it for any type of global business either it is legal or illegal.