Crimes like tax evasion and money laundering? Government should act faster in regulating cryptocurrency before it gets out of hand. Terrorist being funded by bitcoins, kidnappers asking for bitcoins as ransom...
Seriously,you think bitcoin is the only way for criminals to deal things,terrorism and money laundering is going around for a very long time,even before bitcoin and now everyone wants to put their hands on bitcoin to blame,that is just weird. Criminals will always find a way to do their activities.