unit 2 forensics and crime scene investigation ver 4
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Forensic Science 2TRANSCRIPT
UNIT 2 THE FOUNDATIONS OF CRIME SCENE
INVESTIGATION
Overview
In unit one, you would have been previously exposed to the basic concepts in forensic
science, its history, the role and the function of the forensic scientist. Every discipline has
principles governing the delivery of what it is expected to convey. Therefore, the
principles should follow a pattern of investigation to enable the most suitable outcomes.
It stems from criminal investigation to appropriate crime scene investigations, to the
presentation of evidence in the law courts. This unit is geared towards allowing you to
identify the principles of forensic science and to have a better understanding of how these
principles function in this forensic science.
Unit Objectives
After completing this unit you should be able to:
1. Explain crime scene investigation
2. Assess various crime scenes
3. Explain the techniques in crime scene investigation
4. Describe the sociological and psychological techniques in crime scene investigation.
Readings Available:
Saferstein, R., 1998, Criminalistics: An Introduction to Forensic Science 6th
ed., Prentice
Hall NJ.
Session 2.1 What is Crime Scene Investigation
Learning Objectives
At the end of this session you should be able to:
1. Define crime scene investigation
2. Differentiate between primary secondary and microscopic crime scenes
3. Identify techniques in crime scene investigation
4. Explain what crime scene investigators do.
Introduction
Crime scene investigation is an exciting part of forensic investigation. It is absolutely
important for forensic scientists to be equipped with the necessary skills to conduct
thorough crime scene work and to be able to reach a scientific conclusion.
In this session, the crime scene and the crime scene investigator will be defined. The
sociological as well as the psychological aspects of crime scene investigation will also be
defined with particular interest in criminal profiling as a major psychological crime scene
technique. A complete understanding of the various interviewing methods and techniques
will be necessary in appreciating the crime scene.
What is crime scene investigation?
Crime scene investigation is a step by step process in which the forensic scientist
identifies, collects, examines, preserves, interprets, recognizes and reconstructs all
physical evidence in order to solve a crime. Forensic examination of physical evidence is
crucial and forms the basis of the scientific investigation. The physical evidence
distinguishes one suspect from another and is the most convincing form of proof. The
crime scene investigator collaborates with the forensic crime laboratory which examines
the physical evidence to provide investigators with the appropriate information regarding
the evidence in the attempt to solve cases. The crime scene investigator must be able to
use analysis skills, and various techniques, as well as be aware of the linkage principles
regarding the evidence that will allow him/her to be able to reconstruct the crime scene.
Crime scene investigation must therefore be properly managed and investigated in the
most appropriate manner.
Activity 2.1
Activity 2:2
Crime scene investigation is governed by a set of principles and
procedures.
Activity: What’s Your Definition?
Try outlining your personal definition of crime
scene investigation.
Activity: Create Your Crime Scene
Create a simple crime scene and post in the discussion
forum. View the following video for some ideas
http://www.youtube.com/watch?v=O2kkccZsewM
Create a crime scene and post in the discussion forum.
Discuss the crime scenes posted with your classmates.
What is a crime scene?
A crime scene can be classified as the site of the original or first criminal activity where
a crime took place. A crime scene can either be primary or secondary. Crime scenes are
inconsistent and no one single approach works in determining the ultimate crime scene.
The ultimate crime scene is a combination of different classifications that is determined
by the crime scene investigator. The crime scene investigator must be skilled at
evaluating and must frequently evaluate the area referred to as the crime scene. (Miller,
2003)
Primary crime scene - The primary crime scene is the place where the actual
offense took place1 and hence is the site of original activity.
Secondary crime scene - A secondary crime scene is the place in some way, shape,
or form, that is related to the offense but is not the place where the offense occurred2. A
secondary crime scene may therefore be any subsequent crime scenes associated with the
original scene of the crime.
In general, primary scenes hold more usable clues than do secondary scenes but not
always3. Sometimes, the only crime scene that crime scene investigators have to go on is
the secondary scene - the place in the woods where the perpetrator dumped the victim's
body. Under such circumstances, forensic investigators may not know the primary scene
where the killing occurred and therefore they may be forced to rely on the use the clues
found at the secondary scenes to help them establish the identity of the offender or locate
the primary crime scene.
1 Source: http://EzineArticles.com/932577
2 Source: http://EzineArticles.com/932577
3 Source: http://EzineArticles.com/932577
Microscopic Crime Scene: - This scene is composed of several scenes. The following is
a representation of many different crime scenes under microscopic review. A victim’s
body found dumped in a filed represents the several crime scenes within the overall crime
scene of the field: the body, the body’s wound, and the area around the body.
Other classifications of crime scenes are those based on the type of crime committed such
as; sexual assault, homicide or robbery.
Physical location: Crime scenes are also classified according to physical location. This
includes whether the crime scene is indoors, outdoors or via a vehicle.
Activity 2.3
Types of information obtained from the crime scene investigation.
1. Information on the Modus Operandi- This is a specific pattern of how the
offending criminal behaved. This identifies one criminal from another. Criminals
repeat their behaviour and a particular behaviour becomes a criminal’s signature
or a preferred way of carrying out crimes. For example burglars frequently gain
entry into scenes using the same techniques.
Activity: Crime Scene Information
1. Make a list of some of the important information an
investigator may collect from the crime scene.
2. Describe how a detailed analysis of a crime scene should be
conducted?
3.
2. Information on the Corpus Delicti- This is the determination of the relevant
facts of an investigation. This includes the physical evidence, the patterns of the
evidence as well as the laboratory examination of the evidence. The red stain in a
bathroom may be significant to an investigation, but may be extremely relevant if
the DNA matches that of the victim.
3. Linkage of Persons, Scenes, and Objects- The most imperative and common
type of linkage is the ability to link suspects to victims in any criminal
investigation. This can be accomplished by physical evidence in any case. In
addition, liking victims and suspects to objects and scenes can be accomplished
by the use of physical evidence.
What does crime scene investigation involve?
1. Identification of suspects: Identification of physical evidence is a procedure that
involves comparison testing. This can be achieved by fingerprint testing that identifies an
individual. Fingerprint evidence is the best example of comparison testing. The
identification of a suspect is accomplished by recognition, identification, and
individualization of the physical evidence that may point to that suspect. Additionally,
DNA data allows a single fingerprint or blood stain found at the crime scene to identify a
specific suspect.
Activit
Activity: All About Fingerprints
http://www.youtube.com/watch?v=0OL7hE2l_70
http://www.youtube.com/watch?v=R0e8WXkFA64
http://www.youtube.com/watch?v=iomWm3_Qvhk&feature=r
elated
http://www.youtube.com/watch?v=IrpTqKkgygA
2. Identification of unknown substances: This involves the identification of drugs,
poisons or any other substances.
3. Individualizing the evidence: This process involves the use of fingerprints to
distinguish one individual from another. A single finger print found at a crime scene or
even a small blood stain can identify a suspect.
Providing Investigative Leads: This is a very important process of crime scene
investigation. Leads such as physical evidence can assist the investigator in determining
specific details regarding a bag or footwear. The investigator must bear in mind that not
every crime scene has individualizing physical evidence for e.g fingerprints, but every
crime scene contains some form of physical evidence that helps the investigator. The
size, type and colour of a suspect bag, or shoe can easily be identified.
4. Reconstruction of a crime scene: This is the final step in the examination
process and it involves determining and eliminating the events that occurred at the
crime scene. The use of logic, interpretation, careful and naturalistic observation
and reasonable explanations are used. The cornerstone of reconstruction is to
incorporate physical evidence with trace evidence. Crime scene reconstruction
follows scientific principles such as hypothesis formulation, theory formulation,
and logical methodology. The use of logic, careful observation, preserving and
interpreting all data concerning the physical evidence, patterns and impressions of
the victim will be reviewed, organized and studied.
Activity 2.5
Activity 2.6
Summary
In this session you were introduced to various aspects of a crime scene. What constitutes
a crime scene including the physical location, the linkages to suspects and victims, the
importance of proving investigative leads as well as reconstructing the crime scene were
all highlighted. You should have a better appreciation of the necessary steps.
Activity: Think you can Reconstruct a Crime Scene!
Using the information provided below let’s try to recreate this crime
scene.
It’s June 25, 2011. There is a bedroom with a broken window pane. There is
the body of a female lying in the bed with a gunshot wound to the head. A gun
is in the victim’s hands and there is a blood stain on the pillow. There are two
glasses of unfinished wine on the side table
You may use diagrams and explanations to recreate your crime scene.
Share your recreation with your classmates and discuss the submissions
of others.
Activity: Crime Reconstruction Examples
http://www.youtube.com/watch?v=e3E2AMgDf5Y&feature=related
http://www.youtube.com/watch?v=QVzwa-DQRu4&feature=related
Session 2.2 Sociological and Psychological Foundations of Crime Scene
Investigation
Learning Objectives:
By the end of this session students should be able to:
1. Outline the sociological and psychological factors that affect crime scene
investigation
2. Appreciate the role of criminal profiling in crime investigation
3. Describe steps in the criminal profiling procedure
Introduction
The sociology of crime scene investigation raises questions about the relationship
between the individual and society, the nature of crime evidence and social justice.
This gives one an appreciation of how social patterns of behaviour can provide predictive
relevance and meaning in a social context. Therefore, in order for forensic scientists to
have a better understanding regarding crime scene investigation, they should seek to
understand the connection and similarities between sociology and crime scene
investigation.
The individual and society- the individual functions in a social context in society. Crime
is considered a social problem and is any act that violates criminal or civil law. If an
individual violates the in law in any manner, it can be considered a crime.
Social justice- victims of a crime as well as their relatives look to the criminal justice
system to render social justice after a crime has been committed. The forensic scientist
works in collaboration with the criminal justice system to bring perpetrators of crime to
justice in a fair and systematic manner. Social justice holds the view that everyone needs
to be protected under the rules of the law and should be able to conduct their business on
a daily basis without feeling threatened by anyone. If violated in any manner, the justice
system is in place to protect citizens accordingly.
Psychology of Crime Scene Investigation
Many students are fascinated about the field because of their desire to be like Clarice
Starling of The silence of the Lamb. The psychology of criminal activity is a fascinating
area of study and crime scene investigators often apply psychological analysis in order to
solve crimes. The ultimate goal of using psychological intervention is to be able to
understand how criminals think. Forensic scientists often scan the crime scene combing
for evidence that eventually leads to the offender. In order to effectively do this, a
criminal investigation must begin by examining the origins of profiling criminals. The
forensic scientist works in conjunction with the forensic psychologist to help profile
suspects and bring them to justice. Profiling of suspects is crucial to the understanding of
criminal activity. This entire process is called criminal profiling.
Criminal Profiling- this is the ability to outline physical and psychological qualities that
link criminal or deviant behaviour to a specific crime. It is an attempt to provide
information about a suspect. It consists of examining a biographical outline of
behavioural patterns, motivations, trends, tendencies type of weapons used,etc. Criminal
profiling is based on the premise that people behave according to their pattern at the time
of action.
Activity 2.7
Approaches to Criminal Profiling
Distinguishing the Evil Person
The profiler needs to understand the behaviour and motivations of the offender. One must
be able to predict the behaviour while persons play specific roles. For example a
prominent profiler indicated that Adolf Hitler’s childhood relationship with his parents
had a major impact on his later behaviour. Hitler witnessed his father being brutally cruel
to his wife and children causing them pain in the process. Therefore, Hitler’s approach to
adversity and human beings was the same.
Determining Common Characteristics
To determine common characteristics is to carefully examine consistencies in
personalities, backgrounds and behaviours of offenders who carry out similar offenses.
One may ask the following questions.
Are all rapists alike?
Are all murderers alike?
Activity: Criminal Profiling – A dramatization
http://www.youtube.com/watch?v=CMjIk-pRtYo
The Possible Reality! -When we miss the signs
http://www.youtube.com/watch?v=WA33rKJWwI8&feature=
related
This involves the process of crime classification a concept that was mentioned earlier in
this unit. Characteristics can be determined by assessing the childhood background of
suspects and looking for similar experiences. For example, in a research conducted by
(Sullivian & Sevilla,1993) the researchers discovered that out of 41 men, 31 of them
who had committed raped reported that they had been sexually abused as children.
Extracting Specific Characteristics
This is assessed by carefully looking at the Modus Operandi (MO). The Modus Operandi
is also referred as the “Standard Procedure” meaning the way how the suspect carries out
his/her crimes. The MO represents the signature of a person and this distinguishes one
suspect from another. The profiler must examine whether there are psychological or
physical characteristics that can be drawn from the crime scene to profile a suspect. The
profiler must also determine whether patterns of behavior; past or present; resemble
patterns from previous cases.
The signature- this reflects unique and personal aspects of the criminal act but this is
often seen in cases of sexual nature.
The Forensic Psychologist-
The forensic psychologist works closely with the forensic scientist and the criminal
justice system in a number of ways.
As a criminal profiler – They identify suspects and are able to link individuals
according to personality, sex, attributes and characteristics. It is the job of the
forensic psychologist to identify and examine the most common and prevalent
forms of these unique traits. They identify these characteristics based on specific
information regarding the victim as well as the method of criminal activity.
Persecution Process- Forensic psychologists also play a pivotal role throughout
the prosecution process. They provide testimony when suspects are on trial. They
testify as expert witnesses in court and as a reliable source on the validity of
forensic evaluations.
Psychological Assessment of Perpetrators- It is the job of the forensic
psychologist to assess perpetrators both in civil or criminal cases. The
psychologist is concerned with whether the offender was suffering from any
mental disease at the time of the criminal offense and if he/ she would be a threat
to society.
Psychological Techniques in Crime Scene Investigation
Crime Analysis- this focuses on the dynamics of the crime scene and this is another way
of profiling places and suspects. The profiler makes an educated guess based on past
experience. This is referred to as a hypothesis. This is an idea to explain an observation or
the result of an experiment. A major element of any hypothesis is that it must be testable.
A null hypothesis is often used in forensic science. In this approach, the forensic scientist
starts with a hypothesis that can be disproved. Meaning, if he/she is testing a blood
sample, the null hypothesis might be that the blood did not come from a potential suspect.
It is only a hypothesis at first, but by using comparative DNA testing the forensic
scientist will have the opportunity to prove/disprove the hypothesis.
The Criminal Profile Generating Process
This process is comprised of several steps:
1. A comprehensive study of the nature of the crime and the types of persons who
have committed similar offenses in the past.
2. A detailed analysis of the crime scene.
3. An in-depth examination of the background and activities of the victim or victims.
4. Formulations of motivating factors for all parties involve.
5. The development of a description of the potential perpetrator based on overt
characteristics from the crime scene and past criminals’ behaviour
(Wrightsman,2005)
Activity 2.8
Summary
In this session, defining the sociological and psychological aspects of crime scene
investigation is pivotal to understanding the behaviour of suspects and victims from a
sociological as well as a psychological perspective. Unique pertinent details can help
solve a case a bring perpetrators to justice.
Activity: Procedural Steps - A Discussion
Based on the five procedural steps outlined above:
Write a 300 word essay outlining the importance of each
step.
Also discuss how the omission of any one step may
jeopardize the investigation.
Session 2.3 Interviewing and Investigation Techniques
Learning Objectives:
By the end of this session students should be able to:
1. Differentiate between interviews and interrogations
2. Explain the interviewing and investigative techniques in crime scene
investigation.
3. List investigative skills needed by Forensic Scientists
4. Outline various methods of interrogation
Introduction
Techniques in criminal investigation are used to help forensic personnel fit pieces of
evidence/information together. To this end various types of interviews and interrogation
techniques are available to forensic personnel, e.g verbal and non-verbal communication
as well as observation. Additionally forensic personnel must also take into consideration
the type of questions used, or whether inappropriate use of force was utilized. The
concept of false confessions, detecting deception and other forms of manipulations are
areas of concern. Interviewing the victim and the suspect, examining the offender’s
statement, and looking at vulnerable witnesses are all necessary throughout this process.
First Responders.
The first responders at a crime scene are usually police officers, fire department
personnel and other emergency personnel. They are the ones to come into contact with
the crime scene first and are usually the ones to view it in its original state. These
individuals begin the process and their actions at the crime scene provide the basis for a
successful or unsuccessful investigation. They must always keep in mind that the process
begins with them and that they begin the process that links victims to suspects. The first
responders must always maintain an unbiased approach.
Development of investigative skills:
The following skills are necessary in carrying out investigative work for all forensic
personnel:
Objectivity: professional and personal responsibility; self-monitoring;
moral and ethical behaviour; respect and impartiality must always be part of this process.
Communication: Both verbal and nonverbal communication skills are important as well
as being attuned to cultural/social differences. Forensic personnel also need to develop
effective listening skills
Interpersonal Skills: Effecting and maintaining adequate social and relationship skills;
dealing with conflict and ambiguity; ethical use of investigative powers; developing
accurate written and verbal presentation skills; and the appropriate demeanour when
giving evidence in court.
Assessment skills: Assessing the situation; accurate and ethical recording of crime and
potential sources of material for evidential value; collation and analysis of information;
developing and testing hypotheses; identifying links and drawing conclusions;
interpreting evidence; writing accurate reports/papers
Questioning
Most questioning and investigation is done by the crime scene technician or investigator
who is referred to as the forensic specialist. The technician is someone who analyzes and
obtains evidence at the crime scene and reports the findings to the relevant authorities.
The technician questions possible suspects and all those who may be associated with the
criminal offense.
Interview vs. Interrogation
Interview
The difference between an interview and an interrogation is that an interview is
conducted in a cordial atmosphere where a witness is more comfortable physically and
psychologically. On the other hand, whenever a person is questioned in an uncomfortable
atmosphere (interrogation room) where he/she is under any psychological pressure, it is
an interrogation. The interrogator, in this case, has more psychological advantage than
his/her suspect. Interrogation is a kind of psychological warfare between interrogator and
suspect. Only when an interrogator overpowers a suspect psychologically, the
interrogator may get a confession, or the facts of a case which may not have been
previously revealed.
Activity 2. 9
Activity: Develop Your Interviewing skills
These videos may help you develop the skill you need!
http://www.youtube.com/watch?v=Zt_rnt7wbbI&feature=related
Can you easily detect a lie, or spot a liar?
http://www.youtube.com/watch?v=SbH781mVa4E&feature=related
http://www.youtube.com/watch?v=CAHUTNTCaSU&feature=related
http://www.youtube.com/watch?v=E3PAW7zjgPw&NR=1&feature=fvwp
Interrogation
Interrogation is an art. Every good investigator is not necessarily a good interrogator. To
be a good interrogator you need to be a good actor and must have an insight of human
psychology. You also need to be able to apply psychological principles during and after
the interrogation process. Your approach should be different according to the age,
profession and intellect of the suspect because your suspect could be a lawyer, doctor,
scientist, professor, manager or an unskilled laborer. Interrogation techniques are also
affected by the age bracket of the suspect, the suspect could be a child, teenager, adult or
senior citizen.
Prerequisites of an Interrogation:
The following information is necessary when conducting an interrogation:
About the Suspect:
(I) Name, age, profession, occupation of the suspect
(2) Social and financial situation
(3) Criminal history
(4) Relationship with the victim if any
About the Victim:
(1) Name, age, profession, occupation
(2) Social and financial situation
(3) Criminal history if any
Scene of crime:
(1) Time and place of occurrence
(2) Modus operandi
(3 Physical evidence collected
(4) Information collected
Approach
Appropriate places for interrogation:
(a) At the spot when a suspect is apprehended at the scene of the crime
(b) In an interrogation room where the interrogator has more psychological
advantage.
Appropriate time for interrogation:
As soon as the suspect is apprehended and information collected
You should always remember that a suspect is innocent and not a criminal unless
guilt is proved in court.
Don't ever use third degree method.
Always maintain courtesy.
Be a good listener.
Control your anger because in anger you loose reasoning and the judgment made
without reasoning is mostly incorrect.
Never be in a hurry to finish the interrogation.
Methods of Interrogation
We can classify criminals into two major categories:
emotional offenders
non-emotional offenders
The purpose of classification is to vary your approach and methods during the
interrogation of a suspect.
Interrogation of emotional offender:
Interrogation of an emotional offender is much easier than of a non-emotional offender.
An emotional offender is usually a first time offender who can be broken down easily if
the investigator understands how to manipulate the offender’s emotions, of love, hatred,
anger or frustration. This can be achieved by:
By showing sympathy towards the offender.
By telling the offender that anybody would do what he/she has done if placed in a
similar situation.
Blaming the society for the offender’s action.
Being friendly with the offender and offering him/her food or a beverage,
something which an offender never expects from an investigator.
By the investigator keenly observing the offender’s physical reaction and
nonverbal communication to the crime related and non-crime related questions.
When an individual is lying he/she may be under tension. The anti-diuretic bio-
chemical substance released by his/her body leads to the dryness of his/her mouth
and lips. Again, in tense situation an individual may tap his/her foot, play with
his/her fingers, look blankly somewhere else, other than at the investigator. All
these can also be expressed forms of anxiety.
Emotional offenders easily confess when confronted by the evidence that is clear
and compelling.
Interrogation of non-emotional offenders:
Non-emotional offenders are usually hardened criminals. They are professionals who
have probably gained experience committing a series of crimes and either subsequently
have evaded apprehension, or have served many jail terms. They don't like to talk much if
at all. So it’s usually difficult to engage them in conversation for any length of time.
There are several interrogation methods from which an investigator can choose:
Question and Answer Method: This is a common form of interrogation where an
interrogator asks several questions to get the facts of a case. He/she develops his/her
questions based on the facts of the case and the answers given to him/her by the
suspect.
Narrative Method: Always be willing to listen to the suspect. Let the suspect tell his
/her side of story without interruption. Ask him/her to repeat it several times may be
three or four times. He/She maybe have to tell more and more lies just to cover up
one lie. The more he/she lies, the more you have a chance to detect untruthfulness of
the story. Verify his/her story and re-interrogate.
Alibi: Ask probing questions and allow the suspect to speak .Ask where he/she was
and what he/she was doing at the time of occurrence of the crime. Verify his/her alibi
and re-interrogate him.
Factual method: Some criminals are smart and sometimes more than one approach
is needed in order to get information from them. The best way to interrogate a
hardened and professional criminal is to confront the person with the physical and
circumstantial evidence. This may which will eventually lead to a confession by the
suspect.
Sweet and sour method: The use of two interrogators with different styles is
sometimes essential in an investigation. Interrogations conducted by two different
interrogators, one being soft spoken and other being harsh towards the suspect could
be fruitful in some cases.
Overheard conversation method: different approaches wok for different
suspects. Whenever there is more than one offender this method works well. One
suspect while being interrogated should be viewed, but not heard,by the other suspect
from outside of the interrogation room. When the suspect who was allowed to view
turn for interrogation starts, tell the offender that his/her associate has already
confessed about the crime and now it is his/her turn to confess.
Hypothetical situation: Allow a suspect to suggest, even if he/she has not
committed the crime, how would he have done it in the similar situation. Maybe some
important clue could come out of this.
Telling the story backward: Sometimes it is important to ask a suspect to reveal
his/her side of the story from the day before in order to view things from a different
perspective. If he/she has told you what he/she has been doing from the day before
5AM to the present day spanning a period of more than 12 – 15 hours. Then let the
suspect start from the ending period and work backward to the beginning time.
There is no hard and fast rule as to what method you apply to extract the facts or
the confession. It is up to you and, your experience will guide you when
interrogating various kind of suspects. But one should always keep in mind that a
confession, even in writing, is nothing more than a piece of paper unless it is
supported or corroborated by other independent physical or circumstantial
evidence.
Activity 2.10
Activity: Sweet and Sour Method
Watch this scenario
http://www.youtube.com/watch?v=NmO-
a_93bPs&feature=related
Now write your thoughts on the good guy- bad
guy interrogation process.
Post your thoughts in the discussion forum and
react to the thoughts of your classmates
Interviewing of Witnesses
There are various kinds of witnesses such as:
indifference witness
interested witness
hostile witness and
child witness.
An indifference witness is the best kind of witness for a case because the witness does not
have any interest in success or failure of the case. He/She will always prefer to tell
whatever is known about the case without lying, whereas the interested witness may be a
friend, a relative or a potential beneficiary in the case and may embellish aspects of the
occurrence. As for the hostile witness, he/she may have close relationship or friendship
with the suspect and may want to lie to protect the suspect. You may need to interrogate
rather than interview a hostile witness. Most children are volatile witnesses who do not
lie but are vulnerable to the suggestions of others.
It is worthwhile to have an eyewitness to support a case but you should also recognize
that education level, technical knowledge, physical condition, profession and emotions
variables that will impact the eye witnesses’ observation. Don't expect to get one
hundred percent of what happened when the incident took place. An eyewitness may not
observe as keenly as a police officer or other trained investigator would observe.
However, an eyewitness’ information is valuable if it corroborates with the physical or
circumstantial evidence collected. Reconstruction of a case is often important to verify
the truthfulness of the information of an eyewitness.
Activity 2.11
Psychological Autopsy
Psychological autopsy refers to a investigative method used to help determine the mode
of death in equivocal cases. The idea is to find out how the death occurred. It is geared at
finding out whether a death was an accident or a suicide. This is a designed instrument
with 16 items designed to assist the medical examiner. It list 16 behavioural descriptions.
Each item is checked off and the results indicate whether the death was accidental or
suicidal.
Lie Detection/ Use of Polygraph
Police often use various devices to question suspects. The polygraph technique also
referred to as the lie detector has often been used for assessing the honesty of statements
of criminal suspects and to detect lies. The Polygraph measures changes in the suspect’s
body associated with stress of deception – minute changes in alterations in heart rate,
breathing, emotional distress and increase in perspiration. Please be aware that some
persons possess knowledge of how to beat the polygraph test.
Activity 2:12
Activity: Eyewitness
Are you a g reliable eyewitness?
http://www.youtube.com/watch?v=rSzPn9rsPcY
http://www.youtube.com/watch?v=ynpBirT8Nb4&feature=r
elated
http://www.youtube.com/watch?v=bueSHtqk1jM&NR=1
Activity: Polygraph vs. Body Language
Which is more reliable?
Watch the videos
http://www.youtube.com/watch?v=pqjMhNGyDyQ&feature=related
http://www.youtube.com/watch?v=tJXMrJJMNZ4&feature=related
Computerized Voice Stress Analyzer
Computerized Voice Stress Analyzers measure changes in voice frequency in the human
voice that occurs whenever someone is lying. The use of this tool is helpful to an
investigator in order to narrow down the area of investigation even though the results are
not admissible in a court of law due to the probability of evading a deception. However,
when used along with a polygraph test the results can be considered more accurate
Activity 2:13
Summary
In this session you were given the opportunity to be exposed to different types of
interviewing and interrogation techniques. You should find it useful to incorporate all
these important techniques as a forensic scientist.
Activity: Voice Stress Analyzer
Let’s view how it works
http://www.youtube.com/watch?v=uRmVgFWbP6k
Session 2.4 Characteristic in Crime Scene Investigation
Introduction
Like any other skilled profession, the forensic scientist must be skilled as well as
educated in his field of study in order to carry out forensic work effectively. In order to
achieve this, physical characteristics must be paramount. The goal of the crime scene
investigator is to understand how crime scene investigation works and to be skillful in
applying the appropriate techniques and characteristics.
Learning Objectives:
By the end of this session students should be able to:
Discuss the techniques and characteristics in crime scene investigation
The crime scene investigator must be able to endure, use manual dexterity as well as
fortitude.
Endurance: This is absolutely important because forensic work takes time. Not all
crimes can be solved in the same time and depending on the nature of the crime, many
hours are spent putting pieces together much in the same manner as one spends much
time on a gig-saw puzzle.
Manual Dexterity: investigators must be able to use equipment and other aspects of
forensic work properly. Their ability to manage the crime scene is of vital importance to
every case.
Fortitude: crime scene investigators will be exposed to murders, sexual crimes, deviant
acts and things that may make them both physically and psychologically ill. Sometimes
the crime can be heinous and can create some difficulty accepting and staying in course.
A person's ability to accept what happened and to move through it to get the job done is a
quality that is greatly needed to get the job done effectively and efficiently.
The characteristics in crime scene investigation are being able to manage the crime scene
effectively. Crimes today are solved by teamwork of investigators and by large crime
scene personnel using a combination of techniques and procedures to determine evidence,
records and procedures pertinent to the crime being investigated. The crime scene
management entails information management, manpower management, technology
management and logistics management.
Information management- This is the process of gathering and securing important
information relevant to the crime investigation.
Manpower management- This is the process of using all forensic personnel and
determining the most suitable according to the nature of the criminal activity.
Technology management- This is the use of the most appropriate special technology
that must be employed.
Logistics management- This is the ability to work out the fine and pertinent details
regarding the criminal investigation and to rule out information that is not important.
Crime Scene Recognition – The goal of the crime scene recognition stage is to gain an
understanding of the details of the crime scene and to derive a systematic approach to
finding and collecting evidence. The first step is to decide on the extent of the crime
scene. Determine whether the crime is a homicide, suicide, or accident. Assess whether
one victim is involved, or a number of victims and whether blood stains or a trail is
present. The investigator must be vigilant and assess whether blood stains or other fluids
leave a trail in other areas. If this is the case, the crime scene might be the entire
neighborhood.
Securing the crime scene- The idea of securing the crime scene is to be able to link
physical evidence from or to the victim, suspect or crime scene. It is absolutely crucial to
keep unauthorized persons away from the crime scene because anyone entering a crime
scene can alter or change the scene and its evidence. Block off the core crime scene area
for preservation of evidence and current and future investigation.
Crime scene survey- This is also referred to as a “walk-through.” The following
guidelines should be noted.
i) The walk-through approach is to mentally prepare a reconstruction theory
that can be used, changed or utilized as the investigation process unfolds.
ii) It is important to note any transient or conditional evidence that requires
immediate protection or processing.
iii) Be mindful of any weather conditions that may interfere with the crime
scene.
At the crime scene-
Hand Writing Analysis
1. This examines the authenticity of signatures or handwriting.
2. Attempts to identify fraudulent documents
3. Questions typewritten documents
4. Tries to detect forged documents
Activity 2:14
Activity: Crime Investigation Tips
Develop a set of crime scene investigation Do’s
and Don’ts for your local police station.
Post your Do’s and don’ts in the forum and
react to those posted by your classmates.
Summary
In this session you had the opportunity to examine the techniques and characteristics of
crime scene investigation. The concept of managing the crime scene with particular focus
on using manpower, logistics, information and technology all play a crucial role in the
outcome of any criminal or civil investigation. Crime scene recognition, securing the
crime scene and surveying for successful high quality investigation is imperative.
References
http://www. Forensic.com
Wrightsman L. (2003) Forensic Psychology. Thomson Wadsworth.
http://www.education.forensics