New Delhi: The controversial CD containing purported conversations between noted lawyer Shanti Bhushan and political leaders Mulayam Singh Yadav and Amar Singh "is not doctored or tampered with", the Delhi police told a court here.

The Special Cell of Delhi Police has said according to the opinions, received from Central Forensic Science Laboratory (CFSL), New Delhi and the Indian Computer Emergency Response Team (CERT-In) here that there was no editing and tampering with the CD.

The police also said that during his interrogation, Rajya Sabha MP Amar Singh has also confirmed the part of his conversation with Mulayam Singh Yadav.

"Since the opinions given by CFSL Delhi and CERT-In are similar and the CERT-In, having expertise in the information technology, confirms/corroborates the opinion of CFSL Delhi, there is no reason to disbelieve these two reports.

"Amar Singh, MP Rajya Sabha has also confirmed the part of conversation taken place between him and Mulayam Singh Yadav. Hence, it is established during the investigation carried out so far, that the CD in question is not doctored/tempered with," the police said in a report placed before Chief Metropolitan Magistrate Vinod Yadav.

Delhi Police sought permission to close the case filed on the complaint by Bhushan saying there was no substantive evidence to prove the offence of forgery as alleged by him.

Reacting to the Delhi Police report, Bhushan's son Prashant said "we are seeing unfortunately repeated campaigns to try and discredit the members of Civil Society by various smear campaigns to try and show divisions within Anna Hazare's team.

"All these tactics appear to have been adopted by sections of ruling establishment and the government."

In its nine-page report, police said "From the evidence collected during the course of investigation in form of expert opinions, there is neither substantial nor corroborative evidence to prove the commission of offence, within the meaning of section 469 (forgery for the purpose of harming the reputation of any person) IPC. "It is, therefore prayed that the case may pleased be cancelled."

Bhushan had filed a complaint at the I P Estate police station here on April 14, 2011 alleging that the CD, containing his conversations with Mulayam Singh Yadav and Amar Singh, was fabricated and had denied having any conversation with them.

He had alleged that the CD was a "cut and paste job" to discredit the campaign, which was involved in drafting of a Lokpal Bill.

In the CD, Bhushan is allegedly telling Mulayam Singh and Amar Singh that his son Prashant can "manage a judge".

The police said that the CD, which Bhushan handed over to them, was got examined at CFSL, Delhi, and report was received on April 20, 2011 in which it was opined that "the recorded conversation in the CD could not have been tampered" with.

On April 21, the case was transferred to the Special Cell and the CD, received in a sealed cover from CFSL, New Delhi, was sent to CFSL, Chandigarh, for second opinion on April 25, the report said.

CFSL, Chandigarh, gave its findings in a report on May 2 saying that the "recording present in the CD was not original and was a post production edited version" the police said, adding, that as both CFSLs gave different opinion the CD was then sent to CERT-In.

The CERT-In, in its report on May 28, said the "audio file containing the conversation was continuous with no sign of abrupt changes or editing marks", the police said.

The agency said that the CD, which was sent to the office of the Chief Justice of India by a leading daily after it received it at its office on April 13 by some unknown sender, was also got examined by the CFSL New Delhi.

The CFSL here opined in its report that the "recorded conversation in the CD could not have been tampered", it said.

The agency further submitted that opinions of CFSL Delhi, with respect to CD provided by Bhushan and the CD delivered to the leading daily, which was obtained from the office of the Chief Justice of India, were same as recorded conversations in both the CDs were not tampered with.