A senior police official said they have received the report on the CD from the Central Forensic Sciences Laboratory (CFSL) located at Lodhi Road.
Sources quoting the report said the CD does not seem to have been tampered with and there is continuity in the conversation.
"Recorded conversation is in continuity, no abrupt change in speech signal has been detected," the sources said.
The CD and its transcript were shown to complainant Shashi Bhushan, who is co-chairperson of the joint committee to draft the Lok Pal Bill, before it was given to the lab for testing.
Meanwhile, Delhi Police spokesperson Rajan Bhagat said the case has been transfered to the special cell for investigations.
Delhi Police had on Monday given the CD to the laboratory for forensic analysis after Bhushan provided them with a copy of it.
Police had earlier registered a case under Section 469 (forgery intended to cause disreputation) against unknown persons on a complaint filed by Bhushan, who alleged that the CD was forged and intended to malign his reputation and derail the process of joint drafting committee on Lokpal Bill.
Bhushan's son and lawyer Prashant had claimed that the disc was "doctored" using 2006 conversations of Mulayam Singh Yadav and Amar Singh and was intended to influence judgements in 2G and Amar Singh tape cases besides derailing the joint committee proceedings.
He had claimed that the forensic analysis done by US expert George Papcun and Hyderabad-based Truth Labs had shown that the CD has "multiple gaps and signs of electronic editing at very very critical places".
The purported telephone conversation among Shanti Bhushan, Yadav and Singh showed attempts at influencing a judge.