His remarks came against the backdrop of Delhi Police filing a closure report in a city court claiming that the CD was "not doctored or tampered with" as alleged by him.
"Somebody very high up, either some minister or a very powerful Congress politician is behind the fabrication of this CD and that is the reason why Delhi Police is not investigating the matter properly," said Bhushan.
He said the first thing police should have done was to go and record a statement from Yadav as to whether any such conversation took place or not.
"If he had said that there was no such conversation, then they should have recorded a statement of Amar Singh as to on what base this conversation took place," he said.
In the CD, circulated to media houses in Apr after a fast by Anna Hazare for a strong Lokpal, Bhushan is allegedly telling Yadav and Amar Singh that his lawyer-son Prashant can "manage a judge". Bhushan had alleged that the CD was a "cut and paste job".
The CD was circulated soon after a fast by Hazare for a strong Lokpal. Hazare''s close associate Bhushan was named the co-chair of the joint committee to draft Lokpal Bill.
Prashant Bhushan said they were seeing "unfortunately repeated" campaigns to try and discredit the members of civil society by "various smear campaigns" to try to show divisions within members of Anna Hazare and members of the team.
"All these tactics appear to have been adopted by sections of ruling establishment and the government," he told reporters here.
Bhushan said it appeared that some police officials, forensic agency officials, some in government and others have entered into a criminal conspiracy.