Four of the seven convicts in the case.
The families of the victims of the 1991 blast that killed former Prime Minister Rajiv Gandhi approached the Supreme Court on Sunday against the Tamil Nadu government's decision to release the seven convicts in the case.
Abbas and John Joesph from the families of the victims, a Tamil Nadu Congress spokesperson Americai Narayanan and three others have filed a Public Interest Litigation or PIL in the Supreme Court challenging Chief Minister J Jayalalithaa's decision to release Rajiv Gandhi's killers.
The petition says the state must keep in mind not only the interest of the convicts, but also the effect the decision may have on the family of the victims and the society as a whole.
The petition says the decision to release is for narrow political gains and against the constitution. "While the clemency power is vested with Governor and the President under the Constitution... how can remission power be granted to a state," it says.
The court can't intervene once President rejects mercy petitions, the petition says.
Earlier this week, the Supreme Court, acting on a plea by the Centre, stopped Ms Jayalalithaa from releasing the convicts. The top court on February 27 said it will decide, within a week, on the fight between the Centre and Tamil Nadu over who can decide on freeing all seven convicts.
The seven people have spent over 20 years in jail. Nalini, who was earlier on death row, was granted mercy on the intervention of Rajiv Gandhi's widow and Congress president Sonia Gandhi.
Rajiv Gandhi was assassinated in 1991 by a woman operative of the Lankan Tamil separatist outfit LTTE, who greeted him with a bomb strapped to her chest during a rally in Sriperumbudur in Tamil Nadu. Fourteen other people had died in the attack.
For years, the case has been linked to Tamil sentiment and all regional parties in the state have campaigned for the convicts' release.