A team of NIA sleuths is likely to visit Italy to question four Italian marines, who were witness to the killing of two fishermen off Kerala coast in 2012, after their refusal to come to India for deposition before investigators.

Notwithstanding New Delhi's consistent request to send the witnesses, Rome has made it clear that the four will not come to India to appear before investigators in connection with the case in which two Italian marines are accused.

After Italy's refusal, the Home Ministry has sought the opinion of the Attorney General to suggest the way forward.

Home Ministry sources said only two options are left before India, the first being sending a team of National Investigation Agency (NIA), which is probing the case, to Italy after getting a Letters Rogatory from a court. The Italian Police will question the four marines in presence of the NIA team.

Another option is to take statement of the four witnesses under the Mutual Legal Assistance Treaty signed by both India and Italy. These two ways are acceptable to an Indian court.

Two other options given by Italy -- questioning of the witnesses through videoconferencing or sending questionnaire for the four marines to Rome -- are not admissible in a court.

Home Minister Sushilkumar Shinde and External Affairs Minister Salman Khurshid are said to have no objection in sending the NIA team to Italy.

India has already conveyed to Italy that delay in questioning the witnesses is only jeopardising the future of Massimiliano Latorre and Salvatore Girone, accused of shooting dead two Indian fishermen off Kerala coast on February 15, 2012. Both the accused are now lodged in Italian Embassy here.