His remarks came following a RTI reply that the forensic examination by Central Forensic Science Laboratory (CFSL), Chandigarh shows that the CD was "doctored", contradicting findings of two other such tests.
Bhushan claimed that the PMO in response to RTI of Subhash Aggarwal gave him only Delhi CFSL report and not the Chandigarh report.
"The interest taken by the Home Minister P Chidambaram in this matter and the PMO in revealing the Delhi CSFL report while withholding the Chandigarh CFSL report shows that the Government is behind the dissemination of this fabrication, if not the actual fabrication itself.
"This was the beginning of the repeated attempts by the Government to defame important members of the anti-corruption campaign - an attempt which continues till this day," Bhushan said.
After the CD came into circulation, Shanti Bhushan had filed a complaint with Delhi Police on April 14, alleging that it was fabricated and denied having any conversation with Mulayam and Singh.
"This (Chandigarh) report, after 8 months since it came into existence, has been given to Subash Chandra Aggarwal by the Chandigarh CSFL on Central Information Commission"s order. The Delhi Police refused to give this report to Shanti Bhushan despite his repeatedly asking for the same.
"Despite facts they distributed the dishonest Delhi CFSL report which certified the CD to be genuine to the entire media. Even the PMO in response to RTI of Subhash Aggarwal gave him only Delhi CFSL report and not the Chandigarh report," Bhushan claimed.
He further alleged that Delhi Police did not send the Amar Singh-Mulayam Singh CD to the CFSL lab which would have conclusively shown that all of Mulayam Singh's speech in this fabricated CD had been cut and pasted onto the CD from the Amar Singh tapes, which has been filed in the Supreme Court on 2006.
"Shanti Bhushan had given a copy of the Amar Singh CD to the Delhi Police and we had conclusively demonstrated in a press conference on April 17, 2011 that Mulayam Singh's speech had been merely cut and pasted on this fabricated CD from the Amar Singh tape," he said.