Audio Tapes Tampered, Not Fit for Voice Matching with Ex-CM Biren Singh: NFSL Tells Supreme Court in Manipur Violence Case

“Four exhibits showed signs of modification and tampering... not scientifically fit for forensic voice comparison,” the Supreme Court was informed by the National Forensic Science Laboratory (NFSL) in a sensitive matter concerning alleged audio recordings tied to former Manipur Chief Minister N. Biren Singh and the 2023 ethnic violence in the state.

On October 27, 2025, a bench comprising Justice Sanjay Kumar and Justice Alok Aradhe was hearing a plea seeking a court-monitored probe into the controversial audio clips. These recordings allegedly feature conversations that implicate Biren Singh in instigating or contributing to the ethnic clashes that rocked Manipur last year.

"Tampered and Modified": NFSL Finds Audio Clips Unfit for Forensic Voice Analysis

According to NFSL Gandhinagar, which had received the recordings for expert analysis following Supreme Court orders, the material was compromised and hence unsuitable for drawing any conclusion about whether the voice in the clips matched the former Chief Minister’s.

The bench, reading excerpts from the forensic report, noted:

“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. Consequently, no opinion on similarity or dissimilarity of the speakers in question and the control clips can be offered.”

Background: Ethnic Violence, Audio Leaks and Legal Action

The case stems from a petition filed by the Kuki Organization for Human Rights Trust, seeking a thorough investigation into the audio recordings that surfaced amid ethnic tensions in Manipur during 2023. The tapes allegedly include conversations that raise serious questions about the role of the then Chief Minister.

In August 2025, the Supreme Court had directed that the disputed recordings be submitted to NFSL after expressing dissatisfaction with an earlier analysis by Guwahati Forensic Sciences Laboratory, which failed to offer a conclusive opinion on voice matching.

The petitioner, represented by Advocate Prashant Bhushan, relied on an independent forensic assessment conducted by Truth Labs, a private forensic agency. That report claimed with 93% probability that the voice in a 50-minute recording matched that of N. Biren Singh, based on comparison with an admitted sample.

However, the NFSL, a government-recognized forensic authority, has now rejected the integrity of the audio files altogether, citing clear signs of post-recording modification.

"We Will Give You the Report to Respond": Court Assures Petitioner of Access

In the course of proceedings, Justice Kumar assured Bhushan that the NFSL's findings would be shared with all parties:

“We will give you the report so you can respond to it.”

The bench also directed the Registrar to furnish the final NFSL report dated 10.10.2025 to the parties and adjourned further hearing to December 8, 2025.

When Bhushan highlighted the credibility of Truth Labs and raised concerns about delays and lack of government initiative despite the seriousness of the allegations, Justice Kumar responded that NFSL is regarded as the apex forensic institution in the country.

Bhushan countered:

“Yes, but it is a government lab. And your Lordships know that today, when the government...”

He went on to allege that although the tapes were submitted over a year and a half ago, the authorities had not taken any concrete steps to investigate the allegations.

Government Response: "Tapes Tampered, Situation Now Peaceful"

Appearing on behalf of the Union Government, Solicitor General Tushar Mehta submitted that the NFSL report confirmed tampering of the audio recordings. He cautioned the Court against disturbing the current situation in the state, stating:

“It is now quite peaceful there, and let’s not meddle with that.”

The State of Manipur also took a similar line, with counsel stating that he could not follow the contents of the recording due to unclear audio. Bhushan pointed out that forensic labs are equipped with enhanced tools for voice clarification and analysis, which individual listeners do not possess.

Prior Directions and Timeline

The case, titled Kuki Organization for Human Rights Trust v. Union of India, was registered as W.P. (C) No. 702/2024.

• In February 2025, the Court had first sought a forensic analysis from the Central Forensic Science Laboratory (CFSL).
• Dissatisfied with the lack of clear findings, in August, it ordered a second analysis by NFSL Gandhinagar.
• The NFSL was tasked with determining two aspects: (1) Whether the recordings were edited or tampered with, and (2) Whether the voice in the tapes matched the admitted sample of the former CM.
• The lab was directed to file its findings in a sealed cover within six weeks.

The petitioners maintain that the content of the tapes, if authenticated, would expose grave misconduct on the part of the state’s highest office during a time of violent communal unrest. Meanwhile, the state and the Centre have consistently argued that the law has already taken its course, an FIR has been registered, and requests for verification have been sent to social media platforms that circulated the clips.

What Lies Ahead

With the forensic authority concluding that the recordings were manipulated, the Supreme Court is now faced with deciding whether a further probe is warranted, or if the matter must be laid to rest due to the compromised integrity of the key evidence.

The case is next listed for December 8, 2025, when the Court will resume hearing and review any replies filed in response to the NFSL’s report.

Case Title: Kuki Organization for Human Rights Trust v. Union of India