‘NFSL finds tampering in audio clips allegedly implicating former Manipur CM N. Biren’

The National Forensic Science Laboratory (NFSL), Gandhinagar, has informed the Supreme Court that the audio recordings allegedly implicating former Manipur Chief Minister N. Biren Singh in the 2023 violence were tampered with and not scientifically suitable for voice comparison. Consequently, the laboratory stated that it could not provide any opinion on the similarity or dissimilarity of the speakers, as reported in Live Law.
The disclosure came during the hearing of a plea filed by the Kuki Organisation for Human Rights Trust seeking a court-monitored investigation into the controversial audio clips related to the Manipur ethnic violence. A Bench comprising Justice Sanjay Kumar and Justice Alok Aradhe took up the matter on Monday.
After examining the sealed cover report submitted by NFSL, the Court observed that four of the submitted audio exhibits showed signs of modification and tampering, rendering them unfit for forensic voice analysis. “Four exhibits showed signs of modification and tampering. Therefore, they conclude that the clips are altered and do not constitute the original source recording and are not scientifically fit for forensic voice comparison,” Justice Sanjay Kumar read from the NFSL report, as reported in Live Law.
The Bench further noted, “Consequently, no opinion on similarity and dissimilarity of the speakers in question and the control clips can be offered.”
Appearing for the petitioner, Advocate Prashant Bhushan referred to a separate forensic report prepared by Truth Labs, which found that a 50-minute audio recording was unedited and indicated a 93 percent probability that the voice matched that of the same person in the control sample. Responding to this, Justice Kumar stated that the petitioner would be furnished with the NFSL report to enable a detailed response.
“We will give you the report so you can respond to it,” Justice Kumar said. The Court accordingly directed the Registrar to provide copies of the NFSL’s final report dated October 10, 2025, to the counsel and listed the case for further hearing on December 8.
When Bhushan pointed out that Truth Labs had a credible record, Justice Kumar remarked, “We don’t know, because this (NFSL) is supposed to be the premier forensic lab.” Bhushan replied, “Yes, but it is a government lab. And your Lordships know that today when the government…” He further contended that the recordings had been with the authorities for more than a year and a half without any investigation despite their “very damaging” content.
Solicitor General Tushar Mehta, appearing for the Union Government, submitted that the NFSL report itself confirmed tampering in the disputed recordings. “The disputed recording has been tampered with,” he said, advising against further intervention and asserting that “the situation in the state is now quite peaceful.”
Counsel for the Manipur government said he was unable to follow the conversation in the audio clip, to which Bhushan responded that forensic experts had access to advanced tools and equipment to enhance clarity.
The Supreme Court concluded the hearing by directing that copies of the NFSL report be provided to both sides before the next date of hearing on December 8, as reported in Live Law.