K Ragothaman, who was the head of the investigating team of the assassination case, has brought the then chief of Intelligence Bureau (IB) MK Narayanan to the centre of the controversy.
Narayanan, who is currently the governor of West Bengal, has been accused of suppressing a video which allegedly had captured "human bomb" Dhanu at the Sriperumbudur venue where Rajiv Gandhi was killed on May 21, 1991.
The video tape allegedly showed Dhanu's presence at the venue prior to the former prime minister's arrival.
In his book "Conspiracy to kill Rajiv Gandhi - From CBI files", Ragothaman writes, "The assassin gang, as per our investigation, was very much in the sterile zone for more than two and half hours waiting for its target."
The allegations of the author raised fingers at Tamil Nadu police who had easily got away with the claim that Dhanu had sneaked into the sterile zone after Rajiv Gandhi's arrival at the venue around 10 pm.
The author, in his book also, asserted that "the tape taken by the IB officials was the original one and that the video given to the local police was a substituted one."
The former IB chief also informed that DR Karthikeyan, the then chief of Special Investigation Team (SIT), had allowed Narayanan to go scot-free after conducting a preliminary investigation regarding the missing video.
In his book, the author leaves a question for Narayanan saying, would Narayanan have dared "to damage the goal of the Congress party, irrespective of his personal affiliation to Rajiv Gandhi's family?"
According to Ragothaman, the crucial video tape was suppressed as it could have exposed those people with whom Dhanu had interacted at the venue.
The book created the controversy after 21 years of Rajiv Gandhi's assassination. Now, it will be interesting to see how Congress party or its president Sonia Gandhi will react to this revelations.