Correct, even cryptocurrency is not discovered, money laundering is rampant already. Terrorist,corrupt politicians,illegal businessmen, drug dealers launders money before.  Cryptocurrency add a new channel or medium for this illegal activities as a means of transferring funds to cover and  hide their nefarious activity.

Thats why banks are very strict now, especially when opening accounts. They ask detailed info about your source of funds, and sometimes declined if you mention cryptocurrencies.There are some which requires KYC also. Its hard to trace, but government agencies task to monitor these illegal activities are doing their excellent job.