The Northern Marianas Lieutenant Governor Victor Hocog has been named by a Japanese investor who is suing his family for the non-payment of a $US3.4-million loan.
The loan relates to the procurement of the controversial cargo ship the M/V Luta.
A Japanese investor Takahisa Yamamoto filed an amended lawsuit in federal court last week against Mr Hocog and some owners of M/V Luta for allegedly refusing to pay back the money he contributed for the vessel.
Mr Yamamoto's original complaint only used the term "certain defendants".
He said the former Rota senator allegedly promised to use his political position and influence to ensure that Mr Yamamoto's investment in the cargo ship would be profitable.
The amended complaint claims breach of contract, fraud, and unjust enrichment.
The captain and crew of the MV Luta have earlier complained they are owed thousands of dollars in unpaid wages.