A former Indian Intelligence Bureau Joint Director, Maloy Krishna Dhar, has blasted the conspiracy theories behind the Air India bombing that killed 329 people on June 23, 1985.

The bombing was the worst incident in the history of aviation terrorism before 9/11 and was blamed on the Sikh separatists seeking revenge against the Indian government.

Though international intelligence suggests that this was the handiwork of the Babbar Khalsa, a banned Sikh terrorist group, the separatists have always denied their involvement and have rather claimed that the bombing was a result of the "larger conspiracy" of Indian intelligence agencies to discredit their movement in Canada.

Babbar Khalsa leader and the alleged mastermind of the bombing, the late Talwinder Singh Parmar, mysteriously died in the custody of Indian police in 1992. His killing gave room to speculations that this was a cover-up.

Dhar — who has written several books after retirement including the most controversial, Open Secrets — was once posted in Canada and says he cautioned Canadian authorities through "proper channels" about the possibility of a bombing.

The book suggests that Indian Intelligence once helped a soft faction of the Sikh fundamentalists for strategic reasons.

In an interview with South Asian Post, Dhar denied that the Indian agents were working closely with the main suspects in the bombing.

"Let the public say what it wants to say, but no Indian agent was involved," he said.

"If at all any one was involved, that was out of my knowledge."

Dhar admitted that he had prior information of the conspiracy to bomb the plane but the Canadian authorities could not prevent the incident despite a potential threat.

"We had cautioned the Canadian foreign ministry through proper channels that the Babbar Khalsa might target Indian interests including the Air India planes, yet the foreign ministry did not take much interest in the information."

According to Dhar the warning was either taken lightly or ignored due to lack of coordination between the Canadian Police and the then fledgling Canadian intelligence group, CSIS.

On being asked why Parmar was killed if he was such a prize catch in the Air India case, Dhar said, "I was not handling Punjab when Parmar got killed, so I can’t say how he died."

He suggested, however, that Indian police often get tempted to liquidate suspects in false encounters to avoid the lengthy and frustrating task of getting criminals convicted.