CRIME SCENE INVESTIGATION: THE
EVOLUTION OF FORENSIC TECHNOLOGY
Namratha Udayakumar
(namrathau.2012@business.smu.edu.sg),
Technology and World Change (G20), 1st year student, Bachelor of
Business Management, Lee Kong Chian School of Business
EXECUTIVE SUMMARY:
In
world where brutal crimes are a regular occurrence, the forensics divisions of
police departments play a major role in bringing criminals to justice. From
time immemorial, the police have had various methods of convicting criminals.
Though investigators primarily relied on their intuitive theories in the early
days, such an approach is insufficient at present. This paper focusses on how the evolution of technology in
forensics has helped improve the investigation of crime scenes; from ancient
times when there were no established methods of evidence collection and
processing, and technologies to aid these processes, to present day scenarios
where there are innumerable methods to investigate every possible piece of
evidence from a crime scene.
INTRODUCTION:
According to
Merriam-Webster, ‘Forensics’ is defined as “the application
of scientific knowledge to legal problems; especially : scientific analysis of
physical evidence (as from a crime scene)” (“Forensic”, 2013). In other words,
it “is the science of gathering evidence
to support the facts related to a criminal investigation” (Sexton, n.d.).
Forensic
investigators have the job of collecting and documenting evidence from crime
scenes, analysing it, and identifying possible suspects involved. Such
investigations aim at establishing details such as the approximate time and
cause of death, weapons used, identities of people involved, and all the facts
needed to tie lose ends together and zero-in on those guilty of committing the
crime. This information is used by legal authorities either to clear the names
of innocent suspects or to convict those who are guilty.
Forensic
technology is used in relation to various crimes involving murder, bombings,
arson, and so on. However, this paper will focus mainly on murder (homicide)
investigations, and the technology used therein.
Homicide
investigations go through various stages. When investigators arrive at the
scene, the first thing that is done is a walkthrough, so that they get an
overview of the crime scene. This is done before the body or any evidence has
been touched or moved. The crime scene is then documented as it was found
(National Institute of Justice, 2009a).
Photographing
the scene serves as a permanent record and can be used to recreate the crime
scene, and also used in other investigations. Photographs of the crime scene
should be complemented by written documentation, in order to provide for more
accurate records. It is important for the scene to be thoroughly documented in
its original state, before being released for the collection of evidence
(National Institute of Justice, 2009c).
Evidence
collection begins with an on-site examination of the body, to determine the
exact location in the scene, where the victim died. This is then compared to
the location where the victim’s body is found. This is done by analysing
physical evidence, drag marks, blood spatter, any signs of struggle, and so on
(National Institute of Justice, 2009c). Sometimes, it is possible that the
victim was killed elsewhere, and the body was later transported and placed at
the scene. Investigators must look for signs indicating this possibility as
well.
Evidence
at the scene, such as hair, fibres, blood samples, articles belonging to the
victim or suspects, and others, must be carefully collected and preserved, so
that it can be used in future investigations, and can also be produced for
legal purposes(National Institute of Justice, 2009c).
It is
important to collect personal information from witnesses, for identification
purposes, information regarding their relationship with the victim, how they
discovered the death, and any other statements. Their stories are then analysed
to check if they match up to theories based on crime-scene evidence. Moreover,
the statements of witnesses can be used to establish a sequence of events when
certain aspects of the case are not known, or if evidence is insufficient
(National Institute of Justice, 2009c).
It is
also important to develop a profile of the victim. This is done to establish
the victim’s condition before death, with respect to his/her medical history,
mental health, and social history, in order to determine the possible cause of
death, and the circumstances surrounding it (National Institute of Justice,
2009b).
The
evidence from the scene, along with other background information collected from
witnesses and people known to the victim, help to establish a sequence of
events, and link possible suspects to the homicide, finally revealing the
identities of those guilty of the crime.
The
technology used to gather such information has been evolving over the years,
enabling higher levels of accuracy, reliability, and ease of operation. This
paper aims to trace the developments in forensic technology that have been used
in crime scene investigation.
HISTORICAL PERSPECTIVE:
In the past, it
was not common for a very “methodical” investigation of crime scenes.
Investigations
would be conducted based on whatever evidence was clearly available, as they
lacked the means to look into the details of the crime scene, with respect to
trace evidence, gunshot residue, hair and fibres, and so on.
Investigators
did not have much to work with and the techniques they used were quite
primitive. They did not know how to collect evidence, or process it, to deduce
information about the crime scenes. The conviction of criminals largely relied
on confessions, and testimonies by witnesses.
Quite
often, it was very likely that people would be wrongfully convicted despite evidence
being insufficient to prove their guilt, and other times when the guilty were
allowed to walk free due to the inability to draw accurate conclusions from the
available evidence.
However,
with the passage of time, various developments, discoveries, and inventions
took place, which provided a basis for the technology that is in use today.
Some of these include:
(i)
13th Century:
One of the first
known developments in the field of forensics came about in 1248, when a Chinese
forensic expert, Song Ci, wrote a book called ‘Xi Yuan Ji Lu’ (Collected Cases
of Injustice Rectified). This was the first book about how crimes were solved
using forensics. It explained the basis of distinguishing drowning from
strangulation, and how to determine whether it was homicide, suicide, or an
accidental event that led to the death of a victim (American
College of Forensic Examiners, n.d.).
(ii)
18th Century:
Starting from 1784
investigators began the physical matching of evidence from the crime scene,
with suspects or their possessions, in order to identify those who were guilty (American
College of Forensic Examiners, n.d.).
(iii)
19th Century:
The year 1837, saw the beginning of bullet matching, where bullets from crime
scenes were matched with firearms possessed by suspects. Henry Goddard of
London’s first police force, the Bow Street Runners, was the first to use this
technique. Around the mid-19th Century, arsenic was one of the most
common poisons used to kill individuals. However, there was a lack of reliable
methods to test the presence of this poison in the human body. Mathieu Orfila,
who came to be known as the “Father of Forensic Toxicology”, developed
techniques that made the identification of arsenic in the body, more reliable
and accurate (American College of Forensic Examiners, n.d.; CBS News,
n.d.).
The 19th
century was also the period during which photography was first used to document
crime scenes and evidence (American College of Forensic Examiners, n.d.), and
take “mug-shots” of criminals. In about 1892, Francis Galton first described
the basics of fingerprint analysis (CBS News, n.d.).
(iv)
20th Century:
The 20th
Century ushered in more ground-breaking developments that serve as a backbone
for the techniques used today. In 1901, Dr. Karl Landsteiner discovered that
blood can be classified into different groups (CBS News, n.d.).
In 1910, the first
forensic lab was set up by Dr. Edmond Locard. Dr. Locard was a significant
figure in the field of forensics. He formulated a principle known as ‘Locard’s
Exchange Principle’ (American College of Forensic Examiners, n.d.), which
stated that, “When a criminal comes in contact
with an object or person, a cross-transfer of evidence occurs. The criminal
either removes something from the crime scene or leaves something behind.
Either way this exchange can link the criminal to the crime scene” (Baltimore County Public
Schools, n.d.). This principle forms the basis of forensic investigation even
today.
Later, in 1915, an
Italian scientist named Leon Lattes, developed a method of identifying blood
groups from dried bloodstains (CBS News, n.d.). The procedure is still used by
some forensic investigators today, to test stains on the clothing or other
possessions of suspects. During this period, Calvin Goddard developed the
Comparison Microscope. This was a milestone in ballistics and firearm
identification. It enabled the matching of fired bullets and bullet casings, to
the specific firearm from which it was fired (American College of Forensic
Examiners, n.d.).
Identification of
blood at crime scenes was revolutionized with the discovery of Luminol in 1937,
by Walter Specht, a German forensic scientist. He found that when a mixture of
luminol and hydrogen peroxide is sprayed onto a surface, it will emit a
bluish-green glow, in the case that there was blood present on that surface at
some point of time. This is due to a chemical reaction between the luminol and
hydrogen peroxide mixture with blood, which indicates its presence (American
College of Forensic Examiners, n.d.).
In the 1970s, Roland
Menzel, introduced the use of lasers to locate latent fingerprints (which are
not directly visible to the naked eye). In 1985, Sir Alec Jefferys discovered
that every person has unique DNA, like fingerprints, which was the basis of DNA
profiling. This was yet another revolutionary development in forensics (CBS,
n.d.).
In the late 20th Century,
the FBI introduced the IAFIS, which is the Integrated Automated Fingerprint
Identification System. It is a fingerprint and criminal history database,
operated by the FBI (U.S. Department of Justice, n.d.). Similarly, CODIS, the
Combined DNA Index System, was a software developed to share DNA profiles with
other labs (American College of Forensic Examiners, n.d.).
The
developments that took place in the 19th and 20th
Centuries, serve as a very strong support for the technologies that are used
today. From a historical perspective, these developments brought about great
changes in society in terms of justice and crime-fighting. Though the new
technologies were still in their inception stages, they definitely induced a
transition from the times when pure intuition was used to solve cases, to a
time when actual evidence from crime scenes was beginning to be processed, to
support the theories of investigators.
CURRENT SITUATION:
Present day
forensic investigators analyse crime-scene evidence with the help of advanced
technology, which has been slowly built up from past developments. I have
narrowed down all the technology that is used today, to five categories, which
I feel are most commonly used in the processing of evidence.
(i) DNA
Testing:
DNA
testing can identify biological samples like: blood, saliva, fingernails,
hairs, skin cells, mucus, earwax, urine and other such materials. Such samples
can be lifted off clothing, toothbrushes, hair brushes, tissues, and so on
(National Institute of Justice, 2012).
DNA
testing involves the collection of samples from the crime scene and from
suspects, and subjecting them to tests to determine whether they match or not.
If the samples match, it serves as proof that a certain suspect was indeed
present at the crime scene; if not, there is no such evidence placing him/her
at the scene.
Restriction
Fragment Length Polymorphism (RFLP), Polymerase Chain Reaction (PCR) analysis,
Short Tandem Repeat (STR) analysis, Mitochondrial DNA (mtDNA) Analysis, and
Y-Chromosome analysis are some of the technologies used to analyse DNA samples
from crime scenes (U.S. Department of Energy Genome Programs, 2009).
Once
the DNA samples are tested and analysed, they can be compared with DNA profiles
found on databases, such as CODIS (Combined DNA Index System). CODIS is used by
the FBI, and utilizes computer software to search for matching DNA profiles
which are generated via Short Tandem Repeat analysis. The DNA Identification
Act (1994) authorises the use of this technology in the United States. CODIS
has two indexes: the Convicted Offender Index and the Forensic Index, and it
automatically searches these two indexes for matching profiles (U.S. Department
of Energy Genome Programs, 2009). Upon finding a match, it is possible to link
DNA found at a crime scene, to a possible suspect.
(ii) Fingerprinting:
With
the help of present technology, fingerprints can be lifted off virtually any
surface, for example, door handles, glass, blood smears, and even off dead
bodies themselves. Some of the technologies used to lift fingerprints include
Superglue Fuming, Magnetic Powder, Reflected Ultra-Violet Imaging System
(RUVIS), Alternate Light Sources (ALS), and Polyvinyl-siloxane (gel products)
(Gulick, 2008).
Once
the prints have been lifted, analysing them involves a detailed examination of
the ridges, and comparing various points between the prints in order to find a
match. In the present, after the prints are lifted, they are usually scanned
onto computers and compared with databases, such as the IAFIS (Integrated
Automated Fingerprint Identification System). Such computer programs can
automatically perform the analysis much faster, and produce a shortlist of
similar prints from the database for further investigation. The shortlisted
prints are then manually analysed by investigators, thereby helping to save
time (Oracle Education Foundation, n.d.).
(iii)
Trace Evidence Analysis:
Trace
evidence is another important category of evidence that is collected from crime
scenes. It includes materials such as hair, fibres, chemicals, drugs, unknown
powders and liquids, gunshot residue, pollen, soil particles, debris, tire and
shoe prints, and so on.
Trace
evidence may provide a link between suspects and victims in case the same type
of substance is found on both individuals.
Microscopic
trace evidence may be analysed with the help of a variety of instruments such
as the polarized light microscope, comparison microscope, micro-Fourier
Transform Infrared Spectrometer, Visible Microspectrophotometer, Scanning
Electron Microscope, and Pyrolysis Gas Chromatograph-Mass Spectrometer
(Schwartz, n.d.).
Drag
marks, shoe prints, tire tracks and other such evidence can be lifted and
examined with the help of macro and micro casting devices and electrostatic
lifting devices, and can then be compared with suspects and victims (Schwartz,
n.d.).
Gunshot
residue mainly consists of burned gun powder and can be lifted off various
surfaces. It is analysed mainly with the help of wet chemical tests, namely the
Modified Griess Test and the Sodium Rhodizinate Test. This information, along
with other details such as that from blood spatter analysis, can determine the
approximate distance between the victim and shooter (Schwartz, n.d.).
Even
though the examination of trace evidence with these new methods is a modern
development, it is still a very time consuming and tedious process.
(iv) Ballistics:
“Ballistics
is the area of Forensic Science that deals with firearms; how they are used,
why they are used and why they are used frequently in the practice of murder”
(Claridge, 2013, para. 2).
Crime
scenes sometimes provide evidence of the use of some sort of firearm, such as
gunshot residue (at the scene and on the bodies of victims and suspects),
bullet casings, burn marks on the victim, and maybe even the weapon itself. Guns
have special features that enable their identification. Examination of gunshot
wounds, and related evidence found at the crime scene, could enable the
identification of the particular firearm used, and hence disclose information
about possible shooters. Ballistics experts can identify the type of gun used,
and the distance between the victim and shooter, by analysing various factors
and physical evidence, as well as performing tests with similar weapons
(Claridge, 2013).
(v) Blood
Spatter Analysis:
Blood
spatter analysis is in a way, very similar to ballistics. Blood spatter
analysis involves the study of the patters in which blood is shed at the crime
scene. Such an investigation, could determine various particulars such as, the
height of the suspect, type of weapon used, fatality of the blows, presence of
objects or individuals that prevented blood from falling on to a particular
surface, and so on.
Blood
spatter is usually analysed at the scene, by experts, and also in forensic
labs, by performing tests on dummies with weapons that could have possibly been
used by the suspect.
Comparison between the Past and
the Present:
While comparing
the past and present technologies used in crime scene investigation, there is
no doubt that field of forensics has come a long way.
The past
brought about some revolutionary discoveries and inventions that serve as a
basis for the advanced technology that is in use today.
We can
compare past and present technology based on 3 general stages of crime scene
investigation:
(i) Documentation
(ii) Witness interrogation
(iii) Evidence collection and analysis
(i)
Documentation:
In the past,
documentation of the crime scene was probably not considered as important as
solving the case itself. Documentation mainly relied on written information of
investigators, and hence did not provide a very concrete report of the scene.
It wasn’t till much later, when cameras were invented, that investigators
started photographing the crime scene, as is done today.
(ii)
Interrogation:
Similar to
documentation, in the past, statements of witnesses were written down and were
the only form of proof. However, video and audio recordings provide much more
certain evidence of statements made by witnesses today.
(iii)
Evidence
collection and analysis:
Developments in this
regard, are by-far the most ground breaking and revolutionary.
In the early days,
there were no concrete methods of analysing DNA samples. Eventually the
grouping of blood types, only enabled investigators to identify the blood group
of the suspects, but did not go any further than that. Therefore, it did not
help narrow down the possible suspects of a case to a great extent. However,
the DNA testing technologies that are used today, have the ability to
differentiate samples from one another, and compare them to databases, to
pinpoint the particular individuals to whom the sample belongs. This is a more
effective an accurate basis of linking a suspect to a crime.
In terms of
fingerprinting, investigators would lift prints with the help of adhesive tape,
in the past. Not only did this method restrict them from lifting prints off
softer surfaces, but it also was a very tedious method, as the prints would
have to be manually examined and compared to each other. Present day technology
utilizes a variety of chemicals and lighting devices that can lift prints form
virtually any surface. These prints are scanned onto a computer, and compared
with fingerprint databases, to identify possible matches. Although this
technology is time efficient and accurate, the use of advanced methods like the
Reflected Ultra-Violet Imaging System, Alternative Light Sources, and
Polyvinyl-Siloxane are rather expensive.
Trace evidence
analysis in the past, was more of a superficial examination, in view of the
lack of technology to perform in-depth analysis of various substances found at
the crime scene. Although, there were certain investigators who were able to
solve cases on the basis of trace evidence, it was still not a reliable method
of proving guilt. On the other hand, modern day technology provides various
methods and instruments that can be used to analyse minute bits of evidence, to
provide accurate results.
With regard to
ballistics and blood spatter analysis, though there are technologies to aid
investigators today, it still largely depends on the personal knowledge and
expertise of the investigator. These two categories truly require the
application of knowledge and as time progresses, the knowledge and experience
of investigators will increase from past cases, enabling more accurate
conclusions as to the identification of weapons or firearms. This is evident
from the fact that experts today, can identify the type of weapon used, more
easily than investigators in the past could.
Overall,
I feel that forensic investigations in the past, largely relied on the
intuition of investigators. In contrast, present-day theories regarding crimes
must be backed up with concrete evidence and proof that has been thoroughly
analysed; inconclusive evidence and intuitive theories will not suffice. Moreover,
the techniques used in the past were tedious, time-consuming, and manual
methods. Advances in technology have enabled the development of faster, more
accurate, and automatic systems that can be used to process evidence.
FUTURE CONSIDERATIONS:
In the future,
there will probably be "an increased focus on digital forensics and DNA
analysis as other forensic specialties fall by the wayside. A move toward
greater degrees of automation, the use of new technologies, and the trend
toward smaller workforces have also been evident” (Waters, 2012, para. 3).
Technology
today, is growing leaps and bounds in terms of communication devices; mobile
phones, tablets, computers, and so on. I feel that the forensic industry is
bound to integrate with Information and Communication Technology in the future,
resulting in mobile devices to analyse evidence at the crime scene itself,
instead of having to send it back to a forensic laboratory.
Taking
into consideration, the enormous progress that DNA analysis has enabled investigators
to make in various cases, the development of hand-held DNA analysers is
definitely a possibility (Schiro, 2000). The devices could probably use a
principle similar to that used in infrared photochemical breath testers
(breathalyzers) that estimate the level of alcohol in a person’s blood. It
could speed up the process of identifying various substances found at a crime
scene, and who it belongs to.
I think
we are on the road to the development of such devices, since we already have
“Rapid DNA” machines. Two companies, IntegenX and NetBio have introduced such
machines in the United States. Based on samples introduced into the machine, it
generates the DNA data required to identify individuals (Messmer, 2012).
These
machines are mobile, and can be transported to the crime scene, however they
are not hand held, leaving room for innovation.
Considering
the time and effort involved in the analysis of trace evidence, there is a need
for the development of faster and more efficient techniques and instruments to
detect and analyse such materials, which is also possible in the future.
The full
potential of such technology could be used more effectively, if police
departments worldwide have up-to-date criminal databases with fingerprints and
DNA samples from convicted criminals. This would enable more thorough
investigations of possible suspects. However, this also poses a challenge, as
not every police department in the world has adequate funding to make this
possible.
I think
the future of crime scene investigation lies in the area of hand-held devices,
connected to worldwide criminal databases, to establish identities of people
involved in a crime.
Like any
other form of technology, I think developments in forensics, will reduce human
involvement by a considerable extent, and leave the processing of evidence to
electronic equipment. It is impossible to completely exclude humans, as human
intelligence is still required to process crime scenes. Though there are
extremely small chances of computers and other equipment making errors, there
is still a need for people to go over the results, before confirming their
validity.
Considering
the progress that we have made from the past, to where we are today, it is
reasonable to say, that it is extremely likely that we will see great advances
in the field of forensics.
CONCLUSION:
In the past, the evidence from crime scenes that were looked into, was rather
insubstantial, and incapable of recreating the entire crime scene. This is was
due to the fact that the investigative techniques and procedures that were
used, took up a lot of time and effort. There was no certainty that the
suspect, whom the evidence pointed to, was in fact guilty. Therefore the lack
of appropriate technology resulted in wrongful convictions, as well as the
guilty walking free.
Discoveries
and inventions by notable scientists and investigators in the 19th
and 20th centuries are what started the transition to present-day
technologies. Introductions to fingerprinting and DNA analysis by Francis
Galton and Sir Alec Jeffrys respectively, and Locard’s Exchange Principle are
only some of the milestones that form the foundation of today’s forensic
technology.
Today,
it is possible to analyse practically anything from a crime scene. It is truly
mind-blowing as to how the smallest pieces of evidence can be linked to
suspects. Advanced forensic technology has really helped improve the efficiency
and speed of investigations, as well as the incarceration of criminals.
Theories of investigators can now be backed up by clear-evidence, hence
preventing innocent people from being convicted.
Judging
from where we were, to where we have come today, it is evident that
developments in forensic technology have changed the world by a great extent,
and have revolutionized the way crime scenes are investigated.
However,
this does not mean that we can completely rule out the intuition of investigators.
In some cases, the evidence collected may not be able to tell a complete story,
may be tampered with, or even damaged. Here, intuition plays a role in filling
up the gaps, and providing the missing links. Therefore, we see that although
advanced technology may reduce manual labour, there is still a need for the
coexistence of human and technological intelligence.
We must
also consider the fact that the knowledge of people is increasing. It is up to
us, to apply this knowledge to serve good purposes, rather than to misuse it.
Criminals also have access to this knowledge, and may start to erase their
tracks after committing crimes, which will make it incredibly difficult to
identify and subsequently incarcerate them.
Present-day
technology is very versatile and can perform a variety of functions; however
there is still a problem of costs involved. The differences in funding, between
police departments around the world, may result in inequalities in terms of
access to such technology. Though this may pose a challenge at present, it
opens the doors to innovation in the future. There are companies who have
already started innovating, and developing equipment which are smaller, more
convenient to use, and cheaper to obtain. It is a matter of time before such
technology becomes more widespread.
In
conclusion, there is no doubt that forensic technology has come a long way in
improving the investigation of crime scenes, and further improvements can
definitely be expected.
