"The most suitable time to resolve it were the first 72 hours," Staffan de Mistura, special envoy of the Italian government, was quoted as saying by Italy's ANSA news agency.
"No one could have imagined, on February 15, 2012, that this unheard-of affair involving two marines would be protracted for two long years," Foreign Under-Secretary Mistura said ahead of next hearing of the case in India's Supreme Court on Tuesday.
Mistura said marines Massimiliano Latorre and Salvatore Girone "entered the deadly judicial and political-electoral gears of Kerala".
The marines shot dead two fishermen off the Kerala coast in February 2012, sparking diplomatic tensions between India and Italy.
Indian authorities have given their nod to the National Investigation Agency, which is probing the matter, to prosecute the marines under the Suppression of Unlawful Acts against Safety of Maritime Navigation And Fixed Platforms on Continental Shelf Act. The SUA carries death penalty.
India last week removed the possibility of a death penalty but insisted that the marines would still be prosecuted under the anti-piracy law. Now, they face up to 10 years in jail.
Italy said use of the terror law equates it with being a terrorist state.
Last week, India's apex court set February 18 as the next date for hearing arguments from both the sides on the use of the anti-piracy law. Italy had approached the apex court on January 15 amid fears that the NIA intends to prosecute the marines under the anti-terror law SUA.
The marines, deployed on the Italian-flagged oil tanker MT Enrica Lexie, 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 says it has the right to try the Italians as the victims were Indians on board an Indian fishing boat.
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