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Challenging Locard’s Exchange Principle: Knowing Former Postulates of Forensic Science to Overhaul the Fundamentals

Shweta Sharma

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Indian Journal of Forensic Medicine and Pathology 18((2 Suppl)):p 277-282, April-June 2025. | DOI: https://doi.org/10.21088/ijfmp.0974.3383.18225.29

How Cite This Article:

Sharma S. Challenging Locard’s Exchange Principle: Knowing Former Postulates of Forensic Science to Overhaul the Fundamentals. Indian J Forensic Med Pathol. 2025;18(2 Suppl):277-282.

Timeline

Received : June 29, 2024         Accepted : June 12, 2025          Published : June 30, 2025

Abstract

Fundamental principles of forensic science have one of the most popular of these the exchange principle by Edmund Locard. Locard’s exchange principle is summed up in a statement as “Every contact leaves a trace”. In practical case scenarios it has been observed that such exchange of evidences might not occur at all in a perfectly committed crime. Since, the origins of Forensic Science were not supported by the larger scientific communities due to its indecisive nature. The fundamentals of any discipline of science have a lot of importance in its development in the long years. There has been no mathematical or statistical explanation for Locard’s exchange principle and thus, the reliability of the same has been always questioned. Some studies have suggested likelihood ratio or Bayes factor to support the exchange principle. While few suggest modification of the statement to bring clarity of this principle. It is necessary to match the criteria required for a statement to become a scientific principle with reference to Locard’s principle. The current article is an effort to measure the validity of Locard’s principle including its merit/demerits and encourage the scientific community for complying to standards and corrections required for wider application in field of criminal investigation.


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Data Sharing Statement

There are no additional data available. All raw data and code are available upon request.

Funding

This research received no funding.

Author Contributions

All authors contributed significantly to the work and approve its publication.

Ethics Declaration

This article does not involve any human or animal subjects, and therefore does not require ethics approval.

Acknowledgements

We would like to express our gratitude to the patients, their families, and all those who have contributed to this study.

Conflicts of Interest

No conflicts of interest.


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Cite this article

Sharma S. Challenging Locard’s Exchange Principle: Knowing Former Postulates of Forensic Science to Overhaul the Fundamentals. Indian J Forensic Med Pathol. 2025;18(2 Suppl):277-282.


Licence:

Attribution-Non-commercial 4.0 International (CC BY-NC 4.0)

This license enables reusers to distribute, remix, adapt, and build upon the material in any medium or format for noncommercial purposes only, and only so long as attribution is given to the creator.


Received Accepted Published
June 29, 2024 June 12, 2025 June 30, 2025

DOI: https://doi.org/10.21088/ijfmp.0974.3383.18225.29

Keywords

Locard’s principleBayes factorPrinciple vs statementCriteria for principleCriteria for principle in Science

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Received June 29, 2024
Accepted June 12, 2025
Published June 30, 2025

licence


Attribution-Non-commercial 4.0 International (CC BY-NC 4.0)

This license enables reusers to distribute, remix, adapt, and build upon the material in any medium or format for noncommercial purposes only, and only so long as attribution is given to the creator.


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