The MV Wise Honest was stopped in Indonesia last year after it was found to be carrying coal in violation of UN sanctions.
Washington claims the 17,000 tonne ship's origin had been concealed, and it was also being used to import heavy machinery into North Korea.
The US Justice Department will investigate the ship in American Samoa's port capital of Pago Pago said the US Coast Guard's public affairs officer, Amanda Wyrick.
