- Recently, a Congress leader appeared before the Central Bureau of Investigation (CBI) to submit samples of his voice in connection with his alleged role in three murders by a mob during the 1984 anti-Sikh riots.
Process of Collecting Voice Samples
- An investigating agency generally moves to court, seeking permission to collect a person’s voice sample in connection with a case.
- Such forensic analysis is used to corroborate other aspects of the case.
- A voice sample is generally taken in an echo-proof room for a controlled and noise-free environment and a voice recorder is used
- Forensic officials use international phonetic alphabets while recording a voice sample and ask the subject to pronounce only a small part of the original statement so that both vowels and consonants in the spoken bit can be alternatively analysed.
- The semi-automatic spectrographic method of voice sampling is used in Indian forensic labs while some countries use the automatic method where a likelihood ratio of the voice samples is developed, which increases accuracy.
- The spectrographic method for speaker recognition makes use of an instrument that converts the speech signal into a visual display.
First Instance of Usage
- The US Federal Bureau of Investigation (FBI) first used the technique of voice identification analysis, also known as spectrographic at the time, as early as in the 1950s, but the procedure gained legitimacy in 1962.
The legality behind collecting voice samples
- India’s criminal procedure laws do not contain a specific provision for testing voice samples because it is a relatively new technological tool.
- Collection of semen, and hair samples for DNA analysis or taking general body measurements is routine and has specific provisions under law but for collection of voice samples, the police have to move to court or seek the consent of the accused.
- Section 53 (1) of the Code of Criminal Procedure allows the examination of the accused by a medical practitioner at the request of a police officer.
- The word examination in this provision includes “the examination of blood, blood stains, semen, swabs in case of sexual offences, 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.”
- Here, the phrase “such other tests” is read to include a collection of voice samples.
Observations of Court’s
- 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.
- The SC said that the fundamental rights of the accused would not be violated by collecting a voice sample for investigation.
- In a ruling in 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 dictated by vocal cavities and articulates.
- The samples are collected after having permission in accordance with the law. The sample taken itself would not be evidence, rather they are for comparing the evidence already collected.”