Truly, Bitcoin aids money laundery especially in developing countries. Bitcoin transaction is kept on blockchain which allowed people to traced it, the transactions are never truly anonymous. Many illegal activities going through bitcoin but the evidence still there, including money laundering. However, my concern about sites offering to mixer bitcoin, so it can't be traced right? But, I don't think those mixer sites will easily accept money laundering. That's why some countries issued regulations about bitcoin and exchanges to prevent any kind of those transaction.