Bitcoin exchanges, miners, and cryptocurrency-payment processors, operating in the United States are required to comply with federal Anti-Money Laundering (AML) laws.
That means a cryptocurrency user can be prosecuted for violating a number of federal laws. Anybody who converts BTC to USD and sends the money to or from the United States must comply with all AML laws and regulations.
Such laws and regulations are imposed by the U.S. Treasury Department affiliate, FinCEN. The Financial Crimes Enforcement Network is in charge of enforcing the policies and regulations, which serve as a security measure for conducting any financial activity within the U.S. borders.
You can read a big full article here:
https://coinidol.com/bitcoin-exchanges-must-comply-with-us-laws/