Amit Shah said he was "grateful" to the court for the verdict on Sajjan Kumar. (File)

BJP president Amit Shah on Monday seized on the conviction of Sajjan Kumar in a 1984 anti-Sikh riots case to target the Congress, saying no one had any doubt on its role in the riots and alleged its "leaders and workers went on rampage raising provocative slogans" and "murdering men in cold blood".

Victims of 1984 riots had lost all hope of justice because those responsible for crime against them enjoyed political patronage of Congress leadership, Mr Shah alleged in his tweets.

The Delhi High Court's conviction of Sajjan Kumar has once again assured the victims that criminals of 1984 will not go scotfree, he asserted.

"No one ever had any doubt on Congress' role in the 1984 anti-Sikh riots. Their leaders and workers went on rampage raising provocative slogans, raping women and murdering men in cold blood. Yet no one was ever punished despite multiple commissions and several eyewitnesses," Mr Shah said.

The BJP chief thanked Prime Minister Narendra Modi for setting up an SIT in 2015 which, he said, started re-investigation into several cases of 1984 pending for over three decades.

"I am grateful to the court, which has delivered its judgment, bringing relief to the traumatised families," he added.

Congress leader Sajjan Kumar was on Monday convicted and sentenced to jail for "remainder of his natural life" by the Delhi High Court in connection with the killing of five persons during the 1984 anti-Sikh riots that followed the assassination of the then prime minister Indira Gandhi. The court said the riots were a "crime against humanity" perpetrated by those who enjoyed "political patronage".

Reacting to Mr Kumar's conviction, Congress leaders on Monday said it should not be politicised and the law should take its own course. They also said Mr Kumar does not hold a position of power in the party.