Hyderabad: Two hi-tech labs have delivered diametrically opposing results on the Shanti Bhushan CD, even as the CD remains at the heart of the controversy.
KPC Gandhi is a retired inspector general from Andhra Police. He's also the Chairman of Truth Labs, a private forensic laboratory that insists the Shanti Bhushan CD is doctored.
Gandhi's team compared the Shanti Bhushan CD with telephone conversations between Amar Singh and Mulayam Singh Yadav, recorded in 2006. They were looking for minute jumps in the frequency and amplitude of voices on the CD. What they found instead, were entire chunks common to both recordings, down to the ring tone.
"When we converted the conversations into electronic measurements, they are almost like electronic signatures - perfectly matching. We decided it could not be a one time, single take, one event recording done at one place," said Dr Gandhi.
In a digital recording, sound is converted into streams of zeros and ones. Special software like Gold Wave track unusual changes in that digital pattern.
But such work is heavily dependent on specialists to interpret results. The government's Central Forensic Science Laboratory (CFSL) contradicts what Truth Labs says. It says the electronic background noise on the CD is continuous, indicating that the recording was not doctored.
In the laboratory of truth, and especially in the field of audio forensics, the outcome hinges on the judgement of the specialist doing the test. The problem is, that leaves a chink in its armour, which can be used by interested parties to influence the final result.