A bench headed by Chief Justice P Sathasivam said that the petition filed by the Centre, challenging the Tamil Nadu government's decision to remit the sentences, will be decided by the Constitution Bench and framed seven questions to be decided by it.
It said that the Constitution Bench, which will take up the matter within three months, will also decide whether the sentence of a prisoner, whose death penalty has been commuted to life, can be remitted by the government.
The apex court later on had also stayed release of convicts Nalini, Robert Pious, Jayakumar and Ravichandran in the case.
The Jayalalithaa government had on February 19 decided to set free all the seven convicts in the assassination case.
Santhan, Murugan and Arivu are currently lodged in the Central Prison, Vellore and they are in jail since 1991.