You may have seen a report that the US had seized a North Korean bulk cargo ship, the M/V Wise Honest (great name for a smuggler?). The first report I saw was from GlobalSecurity.org. It seemed to have left off a lot of details like where was it seized and by whom,
“On or about March 14, 2018, the Wise Honest was loaded with coal in Nampo, North Korea. On or about April 2, 2018, foreign maritime authorities intercepted and detained the Wise Honest. Maritime regulations require vessels like the Wise Honest engaged in international voyages to operate an automatic identification system (“AIS”) capable of providing information about the vessel to other ships and coastal authorities. However, despite its March 2018 voyage from North Korea, the Wise Honest had not broadcast an AIS signal since August 4, 2017.”
The report did mention the Coast Guard.
Mr. Demers and Mr. Berman (Assistant Attorney General for National Security and U.S. Attorney–Chuck) praised the outstanding investigative work of the FBI and its New York Field Office, Counterintelligence Division, and thanked the Department of Justice’s Money Laundering and Asset Recovery Section and Office of International Affairs; the United States Coast Guard; and the Department of State for their assistance.
This CourtHouseNews report provides more background. The ship was seized by Indonesian Authorities. and is currently en route American Samoa.