Kolkata, Apr 18 (IANS): Questioning the timing of release of the Narada sting operation footage in which many leaders of the Trinamool Congress were "caught" taking bribe, several of whom are contesting the assembly polls, West Bengal Chief Minister Mamata Banerjee on Sunday said she could have changed the candidates if she had prior information.

Addressing a party rally in the city, the Trinamool supremo, without taking names, accused the BJP of being behind the sting conducted by Narada News. The footage of the sting was released in March.

"An illegal company which has done this in 2014, why did you bring this now after the elections have been announced and candidates declared? If I knew about this earlier, I certainly would have given a thought.

"But after the declaration, I cannot change (the candidates)," Banerjee said about the sting in which many top-notch Trinamool leaders were purportedly caught taking bribe in return for favour to a fictitious company.

Hitting out at the BJP's Lok Sabha poll promise of bringing back black money from foreign tax havens, Banerjee said: "We too will investigate and prove who all are behind this. Where is the promise of bringing the black money? Now you are using black money to do the Narada, don't you have any shame."

Even as she urged the people not to believe the tapes, Banerjee assured of action if any of her party members was found involved.

"If anybody from my party is found to be involved, we will surely take action.

"By resorting to repeated lies, this is being imposed upon you, do not believe in that," she added.