The party also questioned the timing for the release of the book in the midst of the Lok Sabha polls.
"They (BJP) remain remote controlled from Nagpur (RSS headquarters). In UPA, it was the first ideal division of labour, perfect harmonious work for 10 long years," Congress spokesman Abhishek Singhvi told reporters here.
Hitting out at Baru, he accused the former media advisor of "betrayal, greed, ambition and sensationalism" and dismissed his book as a "work of fiction and gossip and is not even good fiction either."
Singhvi lashed out at BJP for making political capital out of the book, saying it was "hard to digest" for the opposition party that the UPA coalition continued for two full terms despite its doomsday projections.
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BJP has used the book to target Congress, saying it has proven true its charge of dual power centre involving Gandhi and Singh in which she had the final word.
He especially faulted Baru for the "fantastic" timing for the release of the book in the midst of Lok Sabha polls.
"People of standard does not do hatchet job of their former employers. It shows the denial of re-employment has traumatised the author. It unfortunately also shows severe character flaws, a serious issue of propriety and ethics," Singhvi said.
The Congress spokesman was harsh on Baru over the timing of the release of the book.
"Greed, commercial profit, betrayal, ambition and sensationalism all coalesced into a very very unsavoury cocktail," Singhvi said.
Another Congress spokesman Randeep Surjewala, speaking separately, said "Baru's current proximity to a strategist of Narendra Modi is well known. Timing of his allegations establish whose political agenda he is seeking to serve".
"Congress decisively rejects this cheap fiction lock, stock and barrel," he said.