Bonino's remarks came ahead of the February 10 hearing of the case by India's Supreme Court, which asked Indian authorities to resolve all disputes arising out of the issue of invoking an anti-piracy law against marines Massimiliano Latorre and Salvatore Girone.
Latorre and Girone "are neither terrorists nor pirates", Bonino was quoted as saying by Italian news agency ANSA. The marines allegedly shot dead two fishermen off the Kerala coast in February 2012, sparking diplomatic tensions between India and Italy.
Italy approached India's Supreme Court on 15 January amid fears that the National Investigation Agency, which is probing the matter, intends to prosecute the marines under the anti- terror Suppression of Unlawful Acts against safety of Maritime Navigation And Fixed Platforms on Continental Shelf Act (SUA).
Rome wants the marines to be tried in Italy.
The SUA carries the death penalty. The marines, deployed on the Italian-flagged oil tanker MT Enrica Lexie, have said they mistook the fishermen for pirates.
They are now staying in the Italian embassy in New Delhi awaiting trial. Rome wants the marines to be tried in Italy, claiming the incident took place in international waters.
However, New Delhi said it has the right to try the Italian personnel as the victims were Indians on board an Indian fishing boat. Premier Enrico Letta, meanwhile, reiterated his commitment to bringing them marines back home.
"From my window (in the premier's office) I can read the banner on the facade of the building that houses (newspaper) Il Tempo: 'Let's bring the marines home'," he wrote in a letter to the daily, published today. "It is a strong and legitimate desire. Above all, it is a commitment of our government," Letta said.