The NIA will ensure that the marines are tried according to Indian laws and that the international treaties do not subvert the process.
The decision was taken as it was felt that the Kerala Police case into the killing of two local fishermen was procedurally flawed and may not stand scrutiny in court. Given the sensitivity of the case, the NAI may have to begin the case from scratch.
Massimiliano Latore and Salvatore Girone, were arrested in February 2012 after they shot at the fishermen, confusing them with pirates.
Meanwhile, the announcement on the special court, as directed by the Supreme Court, will be made by the Attorney General, today.
With the NIA coming into the picture, the Centre hopes that there would be speedy trial of the two Italian nationals.