Written by Mukesh Sharma
FORENSIC SCIENCE requires the concept of uniqueness. For this purpose, it is supposed
that a uniqueness theorem should be applicable in forensic sciences. On the
basis of fundamental mathematics and physics, one can easily evaluate the
theorem of uniqueness in forensic science.
mathematics, a theorem states the uniqueness of a mathematical object, which
usually means that there is only one object fulfilling given properties, or
that all objects of a given class are equivalent. In basic physics, we study the
uniqueness theorem which states that there can be only one solution of
Laplace's equation that satisfies the prescribed boundary conditions.
Similarly, one can evaluate on the basis of experience and observations in the
field of forensic science that every crime scene, tool mark, and other
physical evidence must have unique characteristics.
our experiences and observations, the theorem of uniqueness for forensic
science is termed as “Every crime scene
has unique evidence, even though the crime scene is similar in nature or modus operandi. The physical evidence,
tool marks, and patterns must be unique in nature.” To prove the statement,
we provide in this article a survey of our earlier studies and evaluate the theorem of uniqueness in field of forensic
tells a story, helps an investigator recreate the crime scene, and establishes a
sequence of events. If physical evidence is analyzed and interpreted properly,
it helps the investigation take the right path from the crime scene to the
courtroom—where it is more reliable than testimonial evidence. Therefore, physical
evidence is often referred to as the “silent witness”1. Crime scene
classification labels the site of the original or first criminal activity as
the primary crime scene and
any subsequent crime scenes as secondary2.
Modern classifications of the crime scene are summarized in Figure 1.
The fundamental principle of
forensics is that every contact leaves a trace. Whether the contact is between
a person and another person, between a person and a vehicle, or between a
vehicle and a location—the trace is always unique. Forensic investigators
identify the individuality of those traces and analyze them to explain what has
happened. Evidence at crime scenes may include:
Some crime scene investigation
techniques are complicated and resource-intensive, and therefore may not be
available to all investigators. But while visiting a crime scene, a forensic
expert should search for abnormal or unexpected elements in the space in order to
identify the uniqueness of the physical evidence as the silent witness3.
A standard proposed way for forensic investigation by an expert to analyze a crime
scene is explained via the flow chart shown in Figure 2.
Crime scene investigation may
include a combination of the following types of incidents and examinations:
These types of crime scenes are
always a challenge for the forensic expert visiting a crime scene.
MethodologyConcept of UniquenessIn major criminal investigations
such as homicides, suicide, rapes, hit-and-run, and custodial death, personnel with
more extensive training and experience are likely to be used in processing
crime scenes5. In cases of strangulation or hanging, where
unmistakable signs of death are observed, the forensic officer at the scene
should do nothing to the body. In some cases, the investigation yields results
that point directly to and provide solid evidence against the offender. However,
all cases are unique in nature and some present very peculiar evidence at the
Ground to Establish the Uniqueness ConceptA
brief survey of various case studies demonstrates the concept of uniqueness
between different crime scenes.
Case Study 1 – In
this case study, four family members (a husband, wife, and two young sons)
were found dead in their residence. Initially,
this case seemed to be suicide, due to the presence of insecticide in the food
material available at the scene, and no signs of struggle. After careful
scientific observation of the crime scene by the forensic team, several factors
(e.g. absence of vomit, no insecticide containers or wrappers at the scene) suggested
that this was not a suicide. Due to a large amount of different kinds of
medicines at the scene, we advised police to search for a person familiar with
the decedents who may have knowledge of medicinal sciences or who may be
practicing medicine. On the basis of our direction, the eldest son of the family—who
was practicing medicine in another village—was arrested; he finally confessed
to the crime. This confession was confirmed through toxicology and a postmortem
report showing intravenous injections on all of the victims’ hands.4
Case Study 2 – In
this case study (published in Forensic Magazine5), we report an interesting case of
murder, involving a young married woman, that was unraveled by the crime scene
team. The collection of evidence and the laboratory analysis of exhibits
provided the corroborative evidence necessary to prove the victim’s in-laws
were trying to mislead the investigating officer by fabricating a story
of looting and murder. The entry and exit points and blood analysis proved to
be the unique elements of evidence at the crime scene.
Case Study 3 – This
incident6 was reported in the historic fortress of the village
Jasaana (Rajasthan, India). As part of some modernization and renovation of the
fortress, some arc welding caused a massive explosion. Our team of expert visited
the scene and, taking a forensic point of view, calculated the amount of
explosive materials and the level of explosion. Based on our observations, we
concluded that this explosion might have been caused by gunpowder. Throughout this
we tried to shed light on the features and characteristics of gunpowder explosions,
and we performed the first-ever forensic attempt to estimate the amount of gun
powder that exploded. It was a unique study into the nature of explosives.
Case Study 4 – In this
study7, we reported the importance of
investigating evidential samples obtained at various crime scenes. X-ray fluorescence
(XRF) is used widely in forensic science. Its main strength is its
non-destructive nature, thus preserving evidence. We analyzed the application
of XRF to examine evidence such as the purity of gold and silver jewelry
(Indian Ornaments), remnants of glass pieces, and paint chips recovered from
crime scenes. The experimental measurements on these samples were made using an
X-ray fluorescence spectrometer (LAB Center XRF-1800) procured from Shimazdu
Scientific Instruments (Portland, Oregon). The results are explained in terms of
quantitative/qualitative analysis of trace elements, and how useful X-ray
fluorescence is from a forensic point of view. Trace evidence is the silent witness
of this case study covering laboratory examination; even in this case study, the
results are unique.
Case Study 5 – In
this manuscript8, the authors analyze a
fire incident that occurred in a factory at Nimrana City, Alwar (Rajasthan,
India) on October 29, 2007, in which volatile and inﬂammable chemicals were
used as raw material. Safety precautions should be followed as per standard
operating procedures in the presence of volatile and inﬂammable chemicals, but a
long-term and experienced laborer can readily bypass the safety precautions and
invent shortcuts for routine work—which can result in havoc. Through this
paper, the authors explain the data related to the case that helped in reconstructing
the dynamics of the accident. We also suggest methodology to investigate cases
related to fire or arson. Using the methodology in the investigation of fire
cases, we have proposed, the reported items of evidence were unique.
Case Study 6 – In
this very interesting case
study9, we have tried to explain the
importance of the scene examination and preservation of the crime scene.
Through this paper, the author explains the circumstances that can change the public’s
perception. That is, by using the forensic expert’s view, proper examination of
vehicles, victim’s injury, and details of the crime scene, the public’s doubt
might be resolved. The circumstantial
evidence was unique in nature.
Case Study 7 – In this case
study10, the burned, dead body of a woman was found inside her
house. The doors of the room were bolted from the inside, but the windows were open.
Some tiles had been removed from the clay-tiled roof, and it was alleged that
her husband set her on fire and escaped outside through the hole in the roof.
Careful examination of the scene revealed that the hole in the clay-tiled roof was
created after the fire ignited, and that the tiles were removed from the
outside, not from the inside. This lead the investigation in the other direction.
It was determined that the woman bolted herself in the room and took her own
life while her husband desperately tried to save her by tearing a hole in the roof
from outside. In this case, the unique pattern of pressure on the bamboo sticks
on the roof of the house changed the direction of this investigation.
Case Study 8 – In this article, “Uniqueness:
Concept at Scene of Crime,” we presented three case studies. These studies were
purely part of the development of our concept on uniqueness of the crime scene11.
This article became a milestone and the basis for our approach to the proposed
Theorem of Uniqueness in Forensic ScienceOn the basis of our experiences and
observations in the field of forensic science as reported above in Cases Studies
1–8, the theorem of uniqueness for forensic science is termed as: “Every crime scene has unique evidence even
though the crime scene is similar in nature or modus operandi. The
physical evidence, tool marks, and patterns must be unique in nature.”
Our statement will play an important role for
the forensic expert while visiting crime scenes or while performing laboratory
examinations, to find out the individuality or unique character of physical
evidence, tool marks, and patterns. Therefore, the forensic community should
develop an approach that searches for the unexpected within the crime scene.
DiscussionDr. Edmond Locard’s Exchange Principle might sound deceptively
simple, but for almost a century it has been the fundamental axiom of
crime scene investigation. This is the central guiding principle of forensic
science. Trace evidence is a category of evidence that is characterized by materials
that, because of their size or texture, are easily transferred from one location
to another. In this sense, evidence is like pronouns in language: the thing
itself is rarely examined sui generis, but rather bits of it that have
transferred or something transferred to it that represent the thing (a noun, to
extend the metaphor). Once transferred, they persist for some period of time
until they are collected as evidence, lost through activities, or ignored. The
analysis of trace evidence reveals associations between people, places, and
things involved in criminal activity. The category “trace evidence and silent
witness” encompasses a variety of materials, natural and manufactured, that
require microscopy to identify and analyze. These materials include, but are
not limited to, glass, soils, hairs, fibers, paint, pollen, wood, feathers, dust,
and other detritus of things that surround us in our lives.
These days, forensic science is time-intensive and, above all, painstaking.
Ask any experienced crime scene investigator and he or she will tell you that
their two overriding watchwords are concentration and accuracy.
This is why it’s absolutely vital to make a visual record of the
crime scene as soon as possible. As the renowned medical examiner Dr. Michael
Baden puts it: “The first hour of a crime is critical.”12 The proposed
“theorem of uniqueness” is an approach for the forensic community to trace out
the exact, silent witness which is unique in each and every scene of crime. It
is also suggested that the crime scene should be visited by the forensic expert
as soon as possible.
About the AuthorDr. Mukesh Sharma is the Assistant Director of the Physics Division of the State Forensic Science Lab in Jaipur, Rajasthan, India, where he has visited 623 crime scenes and reported 600 cases. He is a qualified expert in physics (M.S.), material science (Ph.D.), and psychology (M.S.), with 12 years of experience in the field of forensic science and crime scene investigation. He has been awarded many times at the national and international level. Sharma has published more than 135 research articles and eight books in various fields of physics and forensic sciences.
1. James, S. H., J. J. Nordby, and S. Bell. 2009. Forensic
Science: An Introduction to Scientific and Investigative Techniques, 3rd
Ed., CRC Press, Boca Raton, FL.
2. Committee on Identifying the Needs of the Forensic Sciences
Community, National Research Council. 2009. Strengthening Forensic Science
in the United States: A Path Forward. NRC, Washington, DC.
3. Weston, N. 2009. Crime Scene to Court, The Essentials of
Forensic Science, 2nd Ed. (ed. P.C. White), RSC, Cambridge.
B. S., K. N. Vashistha, T. Bairwa, M. Sharma, S. Sharma, and G. K. Mathur.
2010. Trace evidence crack a suicide proved
homicide: A case study. J Forensic Res. 1:103. Online
5. Sharma, M., B. S. Khajja, D. R.
Godara, and G. K. Mathur. 2011. Alleged
case of theft and murder unravel by forensic investigation. Forensic Magazine.
6. Kumar S., P. Jain, and M. Sharma. 2016. Importance
of forensic investigation in explosion: A case study. J Forensic Res.
7. Jha, S. and M. Sharma. 2016. X-ray fluorescence Analysis: Useful for
forensic examination. J Forensic Sci & Criminal Inves.
Dixit, R., J. Surendra, P. Gupta, and M. Sharma. 2015. Unknowingly accident of fire: An expensive omission. J Forensic Res. 6:314. doi:10.4172/2157-7145.1000314
9. Sharma, M., S. Jha, and V. N.
Mathur. 2011. What
can an accident explain: A forensic case study. Indian J. of Forensic Medicine and Toxicology. 5:63–65.
10. Sharma, Mukesh, B. S. Khajja, Mayur Sharma, and S.
Jha. 2011. Study of suspected burning case:
A homicide or a suicide. J Forensic Res. 2:135.
11. Sharma, M. 2015.
Uniqueness as concept of crime scene.
Indian J. of Criminology and Crim. 34(1).
12. Baden, M., and M. Roach. 2001. New York: Simon & Schuster.