The Supreme Court of India on Friday stayed the commencement of trial against two Italian marines accused of killing two Indian fishermen off Kerala coast.
The apex court also deferred the scheduled proceedings of March 31 before special NIA court against the marines.
Senior lawyer for Italian Government and Marines said the intervention of NIA probe was illegal.
"NIA can only be there when there is SUA which is the suppression of piracy act. Once the SUA goes there can be no NIA at all. And everything which has been done till now is absolutely illegal," said senior lawyer Mukul Rohatgi on Friday.
Speaking on strategies for the immunity of the Italian Marines, Rohatgi said they had asked for sovereign immunity, the legal protection that prevents a sovereign state from being sued without consent.
"We have also raised an issue of sovereign immunity which is granted to a foreign state and to the employees of a foreign state and the military of a foreign state are also entitled to the same immunity," said he.
Earlier, India had dropped plans to prosecute two Italian marines accused of killing two fishermen under a tough anti-piracy law earlier on February 24, offering a chance to end a diplomatic row between the two countries.
Italy had strongly opposed India invoking the law, arguing that it would amount to treating the men as "terrorists" and it recalled its ambassador to New Delhi in protest against the delay in the two-year-old case.