The CBI today told the Supreme Court that the special anti-riots cell of the Delhi Police had conducted sham investigations and farce prosecutions in the1984 anti-Sikh riots to apparently shield senior Congressleader and former MP Sajjan Kumar, a key accused. In an affidavit, the agency has urged the apex courtto vacate the August 13 stay granted by it and pleaded itseriously prejudiced the prosecution against the Congressleader. A bench of Justices P Sathasivam and B S Chauhan while taking on record the affidavit posted to September 7 the final hearing of the agency's plea to prosecute Kumar for the riots under Delhi Cantonment police station in which 60 people were killed.The agency questioned the intention of the anti-riot cell of Delhi police in filing status reports on July 31, 2008 in the trial court when the investigation was already been conducted by the CBI.The CBI accused Kumar of attempting to drag the trial on one pretext or the other and said his plea for staying the trial was another such attempt.The apex court had on August 13 stayed for two weeks trial proceedings against Kumar facing murder and othercharges in the anti-Sikh riot cases.It had issued a notice to CBI on Kumar's appeal challenging his prosecution.