Prosecution witness Sheela Kaur, who recorded her statements in an in-chamber proceeding, told District Judge Poonam A Bamba that she received various phone calls threatening that her children would be killed if she named Kumar in the case, said senior advocate H S Phulka, who appeared for the victim.
According to court sources, Ms Kaur told the court that she saw the Congress leader instigate a mob in the national capital's Sultanpuri area in 1984.
The witness also said that the security given to her earlier had been withdrawn after which the judge directed the CBI to look into the matter.
The accused told the court that the witness was unreliable and her testimony should not be believed, the sources said.
The court has posted the matter for further hearing on February 7. Ms Kaur's husband, brother-in-law and father-in-law were killed in the 1984 riots.
Kumar and two other accused, Brahmanand Gupta and Ved Prakash, had said that they were ready to bear the expenses of the videography of proceedings.
The three accused are facing trial on charges of murder and rioting in the case pertaining to killing of Surjit Singh in Sultanpuri.
The proceedings in the case were earlier stayed after the victim and complainant Joginder Singh approached the high court seeking transfer of the case while alleging that evidence was not being properly recorded.
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