Collecting voice samples to aid investigation: process and legality

Subject :Polity

Section: Constitution

Context:

Congress Leader Jagdish Tytler has appeared before the CBI to submit samples of his voice as part of the investigation into his alleged role in three murders in Delhi’s Pul Bangash area by a mob during the anti-Sikh violence of 1984.

How is a voice sample taken?

The sample is collected under controlled circumstances, following specific procedures.
A voice sample is generally taken in an echo-proof room for a controlled and noise free environment and a voice recorder is used.
The subject is asked to say a small part of the original statement that is already part of the evidence, and both vowels and consonants in the spoken sample are analyzed.
Certain technical parameters are kept in mind while collecting the voice sample. A spectral analysis of the audio speech is undertaken where the pitch, energy, and frequency of the voice are kept as the base to study and match with the original audio sample
There are two ways in which a comparison is made
Firstly, The semi-automatic spectrographic method” of voice sampling — that uses an instrument that converts speech signals into a visual display — while some other countries use the “automatic method” where a likelihood ratio of the voice samples is developed, which increases accuracy

Legality to collect voice samples of a suspect or accused

India’s criminal procedure laws do not contain a specific provision for testing voice samples because it is a relatively new technological tool.
Section 53 of the Code of Criminal Procedure (CrPC), 1973, allows examination of accused by a medical practitioner at the request of a police officer.
The word “examination” includes the examination of blood, blood stains, semen, swabs in case of sexual offenses, sputum and sweat, hair samples and fingernail clippings by the use of modern and scientific techniques including DNA profiling and such other tests which the registered medical practitioner thinks necessary in a particular case”.
The phrase “such other tests” is read to include the collection of voice samples.
In a 2013 case, the Supreme Court considered whether compelling an accused to give his voice sample in the course of an investigation would be violative of the fundamental right against self-incrimination or the right to privacy. While delivering a Split Verdict in the case, the SC acknowledged that there is no specific law for collection of voice samples
In a ruling on March 30, 2022, the Punjab and Haryana High Court observed that voice samples in a sense resemble fingerprints and handwriting, each person has a distinctive voice with characteristic features. The sample taken itself would not be an evidence, rather they are for comparing the evidence already collected.”