Bitcoins are now using by criminals in completing their crimes.  As bitcoins allow transaction freedom,  that is transaction across accounts without involving third party,  which means these two persons are not answerable to anyone about how,  why,  when, what like questions.  Bitcoin comes with the freedom of fees less transaction.  Many drugs dealers accept bitcoin in exchange with bitcoin.  Bitcoins offers a number of benefits that allow them to continue their illegal activities without any interference of any authority.