Voice Samples in Criminal Investigations

• 18 Apr 2023

For Prelims: Voice Samples in crime investigations, Central Bureau of Investigation, Right to privacy.

For Mains: The reliability and accuracy of voice recognition technology in criminal investigations, Legal and ethical considerations surrounding the use of voice samples as evidence in court.

Why in News?

Recently, a political leader appeared before the Central Bureau of Investigation to submit his voice samples for corroboration with a particular speech concerning his alleged involvement in in the 1984 anti-sikh riots case.

• Voice samples have become an important tool in criminal investigations, allowing investigators to corroborate evidence and identify suspects.

How are Voice Samples Taken?

• Procedure:
  • Investigating agencies move to the court to seek permission to collect a person’s voice sample. Samples are taken in an echo-proof room for a controlled and noise-free environment.
  • A voice recorder is used to record the sample where the subject is asked to speak a specific clue word from a statement already part of the evidence.
• Methods of Comparison:
  • An anonymous voice sample is compared with a suspect list of five persons; however, when the speaker is known, both the voice samples are corroborated.
  • International phonetic alphabets are used for recording voice where the subject pronounces only a small part of the original statement (for ease of analysis).
  • Voice Sampling in India:
    • Semi-automatic spectrographic method of voice sampling is used in Indian forensic labs.
    • The forensic lab submits the final report to the investigating agency, indicating whether the results of the voice sample analysis are positive or negative.
  • However, in some countries, the automatic method is used, where a likelihood ratio of the voice samples is developed. This increases efficiency.
• Drawbacks:
  • Inaccuracies may arise if the person’s voice is altered due to the effect of medicines or if the person is suffering from a cold.
  • The credibility of the sample depends on the technique used by the expert and how the court analyzes it.

What is the Legality behind Collecting Voice Samples?

• In 2013, the Indian Supreme Court considered whether collecting voice samples would be violative of the fundamental right against self-incrimination or the right to privacy.
• Section 53 (1) of the Code of Criminal Procedure allows examination of accused by a medical practitioner at the request of a police officer to collect samples for DNA analysis or taking general body measurements and "such other tests necessary"
  • The phrase "such other tests" in Section 53 (1) is read to include a collection of voice samples. However, there is no specific provision for testing voice samples under criminal procedure laws as it is a relatively new technological tool.
  • In a split verdict in the 2013 case, the SC also acknowledged the absence of a specific law for this purpose.
• In a subsequent 3-judge bench hearing, the Supreme Court held that the fundamental rights of the accused will not be violated by collecting a voice sample for investigation.
  • It held that the right to privacy cannot be construed as absolute and must bow down to compelling public interest.
• Recently, in 2022, a ruling by the Punjab and Haryana High Court also observed that voice samples resemble fingerprints and handwriting and are collected with permission in accordance with the law and are used for comparing evidence already collected.

What is the Right to Privacy?

• The right to privacy is protected as an intrinsic part of the right to life and personal liberty under Article 21 and as a part of the freedoms guaranteed by Part III of the Constitution.
• The Supreme Court described privacy and its importance in the landmark decision of K.S. Puttaswamy v. Union of India in 2017 that - Right to Privacy is a fundamental and inalienable right and attaches to the person covering all information about that person and the choices that he/ she makes.

What are the Past Cases where Voice Samples were Collected?

• India:
  • A Special Courts under Essential Commodities and Narcotic Drugs and Psychotropic Substances Act (NDPS) had allowed a plea moved by the Narcotics Control Bureau (NCB) in February 2021, seeking the collection of voice samples among 33 accused in a drugs case it was investigating after the death of actor Sushant Singh Rajput.
• Other Countries:
  • The US Federal Bureau of Investigation (FBI) first used the technique of voice identification analysis in the 1950s.

UPSC Civil Services Examination, Previous Year Questions (PYQs)

Prelims

Q. In addition to fingerprint scanning, which of the following can be used in the biometric identification of a person? (2014)

1. Iris scanning
2. Retinal scanning
3. Voice recognition

Select the correct answer using the code given below:

(a) 1 only
(b) 2 and 3 only 
(c) 1 and 3 only 
(d) 1, 2 and 3

Ans: (d)

• Biometric verification is any means by which a person can be uniquely identified by evaluating one or more distinguishing biological traits.
• Unique identifiers include fingerprints, hand geometry, earlobe geometry, retina and iris patterns, voice waves, DNA, and signatures. The oldest form of biometric verification is fingerprinting.
• All the given processes, namely, Iris scans, Voice recognition, and Retinal scanning can be used for biometric identification. Hence, 1, 2 and 3 are correct. Therefore, option (d) is the correct answer

Source: IE