"Sonia Gandhi should answer the people on who helped the two Italian marines get safe passage from India after killing two fishermen in Kerala," he said at an election rally here.
The BJP's Prime Ministerial candidate said people of the country were unaware of the punishment meted out to the marines and it was the responsibility of the UPA chairperson to let them know in which jail of the country the two were lodged in and the quantum of their punishment.
"Two Italian marines had killed innocent fishermen in Kerala but instead of being in jail in India, they were sent back to Italy. They were innocent fishermen fishing in Indian water.
"I want to ask: who or what power sent them back to Italy and asking them not to be brought back. Should they (marines) not be in jail in India," he asked.
He said it was only after the Supreme Court intervened and ordered that they be brought back, that the "powers were forced to ensure the return of the marines".
The BJP's Prime Ministerial candidate said, "The nation now wants to know the address of the jail where the marines have been lodged. Just because they are from Italy, they cannot be subjected to different treatment".
Italian marines Massimiliano Latorre and Salvatore Girone shot dead two fishermen off the Kerala coast in February 2012, sparking diplomatic tensions between India and Italy.
The marines, deployed on the Italian-flagged oil tanker 'MT Enrica Lexie', had said they mistook the fishermen for pirates and were allowed to leave the country.
They are now staying in the Italian Embassy in New Delhi awaiting trial as India has insisted that the marines would be prosecuted under the anti-piracy law and face up to 10 years in prison as the victims were Indians on board an Indian fishing boat.
After a prolonged detention of the marines, the Kerala High Court allowed them to go home in Italy to celebrate Christmas in December 2012.
The Supreme Court had allowed the marines to be taken out of a jail in Kerala and be lodged in the Italian Embassy.