The Union Home Ministry has decided to commute Rajoana's death sentence to life imprisonment.
"We are taking a legal opinion on that. Most probably, we will challenge the Centre's decision on the ground that Rajoana himself had never moved any mercy petition for the commutation of his death sentence," state legislator and the slain leader's grandson Gurkirat Kotli said.
His assertions came a day after Chief Minister Amarinder Singh clarified that his government had merely sent to the Union Ministry a list of all long-term TADA prisoners, and had no role in the Centre's reported decision to release former Chief Minister Beant Singh's killer or any other particular prisoner.
His government had only sent the list of 17 prisoners held under the Terrorist and Disruptive Activities (Prevention) Act (TADA) in Punjab, as required by the Centre, which had taken an independent decision on the release of the prisoners, the Chief Minister said.
He also said the state government was yet to receive the names of the nine prisoners whom the Union Home Ministry had decided to grant special exemption.
Amarinder Singh was responding to reporters in Ludhiana on the Congress' reaction to media reports suggesting that former Chief Minister Beant Singh's killer was among the eight prisoners that the Centre had decided to release as a humanitarian gesture on the 550th birth anniversary of Guru Nanak Dev.
Beant Singh, who played a crucial role in ending terrorism in Punjab, was assassinated on August 31, 1995.
Rajoana was in the list of the 17 submitted by the state government to the Centre as he was a TADA prisoner who had completed more than 14 years in jail, like the other prisoners on the list, he added.
The Congress stand on Beant Singh's killers has always been clear and consistent that they should serve their full sentence, said Amarinder Singh.
He, however, added that he was personally against the death penalty, which he had also said back in 2012.
In his personal opinion, all cases of death penalty should be commuted to life imprisonment.
Hailing the move, five-time Chief Minister and Akali Dal patron-in-chief Parkash Singh Badal has lauded as "statesmanlike, far-sighted and humane decision of the government of India to release eight Sikh prisoners who had already served their full term and to commute the death sentence of Rajoana into life imprisonment."
Badal said these gestures would go a long way in assuaging the hurt sentiments of the Sikh masses during successive Congress regimes.
"Every step that strengthens the hands of the forces of peace and communal harmony and cements Hindu-Sikh unity in Punjab and the country should be welcomed by everyone, overcoming personal factors," Badal said in a statement on Monday.
Whole heartedly thanking Prime Minister Narendra Modi and Home Minister Amit Shah for "the strong positive gesture" on the eve of the 550th birth anniversary of Guru Nanak, Badal said there is a government at the Centre which is friendly to Punjabis and the Sikhs.
"As always, it is left to the NDA government to apply the healing touch to the Sikh wounds," Badal added.
( With inputs from IANS )