Choksi had taken the citizenship of Antigua in November 2017, and oath of allegiance on January 15 this year, the officials said.
The officials said that after getting the confirmation, the agency is likely to move an extradition request through the External Affairs Ministry and may not wait for a Red Corner Notice as the application is still pending with Interpol.
The Citizenship by Investment unit of Antigua and Barbuda had told local newspapers that Choksi's citizenship application was granted after "robust due diligence" and "international investigation" by "reputable agencies", including the International Criminal Police Organisation and the CARICOM Implementing Agency for Crime and Security (IMPACS).
The CBI, the nodal agency of India for Interpol, said no information regarding background checks of Choksi was sought from it by the international agency.
"The Interpol has not sought any information related to Choksi from the CBI in the last three-four years," CBI spokesperson Abhishek Dayal had said.
Under the Citizenship by Investment Program of Antigua and Barbuda, a person can take their passport on a minimum investment of USD one lakh in NDF investment fund.
He escaped India in the first week of January and took the oath of allegiance in Antigua on January 15, they said, adding that the next day the scam blew up.
Choksi's actions show that he had planned in advance his escape and subsequent life knowing that the scam would blow up after the retirement of PNB employee Gokulnath Shetty, who was helping him with renewal of letters of undertaking, the officials said.
Choksi allegedly swindled Rs 7,080.86 crore, making it possibly the biggest banking scam in the country, the agency had said.
An LoU is a guarantee given by an issuing bank to Indian banks having branches abroad to grant short-term credit to the applicant.
Choksi and his companies allegedly availed credit from overseas branches of Indian banks using the fraudulent guarantees of PNB given through LoUs and letters of credit issued by the Brady House branch which were not repaid, bringing the liability on the state-run bank, the officials said.