UNIVERSITY OF SOUTH AFRICA
College of Law – School of Criminal Justice
⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄⋄
SEP1503: Corporate Investigation I
Assignment 01 | Semester 2, 2026
⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄⋄
SEP1503
Module Code:
Corporate Investigation I
Module Name:
Locard Principle, Sources of Information,
Assignment Topic:
Statement-Taking and Corporate Investiga-
tion Case Study
01
Assignment Number:
Semester 2, 2026
Semester:
60
Total Marks:
Submitted in partial fulfilment of the require-
ments for Corporate Investigation I, UNISA 2026
, UNISA | SEP1503 Corporate Investigation I – Assignment 01
Question 1: The Locard Principle
Every physical encounter between a perpetrator and a crime scene, victim, or object leaves
behind a material trace, and this insight forms the theoretical foundation of modern trace
evidence analysis (EBSCO Research Starters, 2024).
1.1 Explanation of the Locard Principle
The Locard Principle, developed by the French criminologist Edmond Locard, holds that the
perpetrator of a crime always brings something into the scene and leaves with something
from it, and that both traces can serve as forensic evidence (Wikipedia, 2026). Locard sum-
marised this idea in the well-known dictum that every contact leaves a trace, understood
as meaning that whenever two objects come into contact, an exchange of material occurs
between them (National Institute of Justice, n.d.). In practical terms, an offender does not
merely act upon a scene or a victim; the offender is simultaneously acted upon by that scene
or victim. Fibres, hairs, skin cells, blood, soil, and even digital traces such as metadata may
pass in both directions, since a person who enters a crime scene leaves trace evidence be-
hind while also picking up material from the surrounding environment (Forensic Science
Simplified, n.d.). This two-way transfer is what gives trace evidence its investigative value,
because it does not depend on a witness having seen the offender; it depends only on the
fact of physical contact having occurred.
1.2 Application to the Scenario: Linking the Suspect to the Rape Attempt
In the scenario, the complainant scratched the face of her unknown attacker while resisting
him. Applying the Locard Principle, this act of scratching constitutes precisely the kind of con-
tact the principle describes, and it produces exchange evidence in at least three directions.
First, the complainant’s fingernails may retain biological material scraped from the suspect’s
face, most importantly skin cells and blood, which are a rich source of DNA, since even a
small amount of skin or a single hair carries a genetic profile that forensic scientists can
match to a specific suspect (Forensic Science Simplified, n.d.). A forensic nurse or district
surgeon can take nail scrapings and swabs from the complainant as part of the medico-legal
examination, and this biological sample can later be matched against a buccal swab taken
from the arrested suspect.
Page 2 of 12
College of Law – School of Criminal Justice
⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄⋄
SEP1503: Corporate Investigation I
Assignment 01 | Semester 2, 2026
⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄⋄
SEP1503
Module Code:
Corporate Investigation I
Module Name:
Locard Principle, Sources of Information,
Assignment Topic:
Statement-Taking and Corporate Investiga-
tion Case Study
01
Assignment Number:
Semester 2, 2026
Semester:
60
Total Marks:
Submitted in partial fulfilment of the require-
ments for Corporate Investigation I, UNISA 2026
, UNISA | SEP1503 Corporate Investigation I – Assignment 01
Question 1: The Locard Principle
Every physical encounter between a perpetrator and a crime scene, victim, or object leaves
behind a material trace, and this insight forms the theoretical foundation of modern trace
evidence analysis (EBSCO Research Starters, 2024).
1.1 Explanation of the Locard Principle
The Locard Principle, developed by the French criminologist Edmond Locard, holds that the
perpetrator of a crime always brings something into the scene and leaves with something
from it, and that both traces can serve as forensic evidence (Wikipedia, 2026). Locard sum-
marised this idea in the well-known dictum that every contact leaves a trace, understood
as meaning that whenever two objects come into contact, an exchange of material occurs
between them (National Institute of Justice, n.d.). In practical terms, an offender does not
merely act upon a scene or a victim; the offender is simultaneously acted upon by that scene
or victim. Fibres, hairs, skin cells, blood, soil, and even digital traces such as metadata may
pass in both directions, since a person who enters a crime scene leaves trace evidence be-
hind while also picking up material from the surrounding environment (Forensic Science
Simplified, n.d.). This two-way transfer is what gives trace evidence its investigative value,
because it does not depend on a witness having seen the offender; it depends only on the
fact of physical contact having occurred.
1.2 Application to the Scenario: Linking the Suspect to the Rape Attempt
In the scenario, the complainant scratched the face of her unknown attacker while resisting
him. Applying the Locard Principle, this act of scratching constitutes precisely the kind of con-
tact the principle describes, and it produces exchange evidence in at least three directions.
First, the complainant’s fingernails may retain biological material scraped from the suspect’s
face, most importantly skin cells and blood, which are a rich source of DNA, since even a
small amount of skin or a single hair carries a genetic profile that forensic scientists can
match to a specific suspect (Forensic Science Simplified, n.d.). A forensic nurse or district
surgeon can take nail scrapings and swabs from the complainant as part of the medico-legal
examination, and this biological sample can later be matched against a buccal swab taken
from the arrested suspect.
Page 2 of 12
