MAKING A
CASE
Interviewing
Witnesses
Interviewing
Suspects
Creating A
Profile
Recognising Faces
Detecting Lies
Top-down
Typology (FBI)
Factors Affecting
Identification
Interrogation
Techniques
Bottom-up
Approach (Canter)
Cognitive Interview
False Confessions
Case Study
(Railway Rapist)
http://www.youtube.com/watch?v=LPNvAT
tE3vA
What is meant by an offender profile?
Why do detectives come up with an
offender profile?
Offender Profiling
There is no single definition of an offender profile and
profiling varies between individual profilers.
The basic premise of offender profiling is that the
information left by the offender at the scene of the
crime in terms of their behaviour and forensic
evidence (their psychological fingerprint) will be
consistent with their everyday behaviour and
therefore conclusions can be drawn about the person
who committed the crime, which will aid their
capture.
Copson (1995) argues that police need 4 types of information from
profilers:
The type of person who committed the crime.
How great a threat they pose in the future?
To what extent is the case linked to others?
How the police should interview suspects.
Profiles are mostly used for certain types of serial offences such as rape,
murder (especially sexual murder), arson and kidnapping. The more
offences in the series, the easier it is to see the consistencies in the
offenders behaviour.
Previous offending
history
Choice of victim
Victim / offender
interaction
Capture style
Signature of offender
Trophies or souvenirs
Nature of offence
Developing a
criminal profile
Timing
Site of offence
Significance of
sexual acts
Body deposition
Pattern of
injuries
Creating a profile: Top-down Typology
The phrase top-down refers to an approach which starts with
the big picture and then fills in the details, this contrasts with
a bottom-up approach which starts with details and creates
the bigger picture.
Both of these approaches have been used to build up profiles
of crimes to aid police in solving crimes and apprehending
criminals.
Both have flaws, in reality it will depend on the situation and
type of crime as to which approach is used.
Creating a profile: Top-down Typology
The initial information was gathered from interviews with serial killers.
This is combined with detailed investigations of the crime scene and information about the nature of the
attacks to develop models that would lead to the creation of a profile.
FBI investigators, Hazelwood & Douglas in 1980 were able to classify crimes in terms of the ‘organised’
and ‘disorganised’ offender by attempting to fit new crimes into these existing categories based on
details of the crime and intuitive analysis.
Ressler et al claimed that a crime scene can be used in the same way as a fingerprint to help in
identifying a murderer, saying that it is possible to categorise this fingerprint as ‘disorganised’ or
‘organised’ from an examination of the crime scene.
This is an example of a top-down typology (typology is a kind of template for a particular type of crime
that has been built up by previous criminals and solved crimes). This approach takes established
typologies and apply them to a new crime.
Creating a profile: Top-down Typology
Killers belonging to these two typologies (organised
& disorganised) would lead very different lifestyles,
have different personality traits, leave very different
crime scenes, demonstrate different post-offence
behaviour and require different interview tactics from
the police.
Differences in the personalities of the organised nonsocial and the disorganised asocial offender should
be reflected in the crime scene.
Creating a profile: Top-down Typology
An organised offender leads an ordered life and kills after some sort of critical life
event.
Their actions are premeditated and planned, they are likely to bring weapons and
restraints to the scene.
They are likely to be of average to high intelligence and employed.
A disorganised offender is more likely to have committed the crime in a moment
of passion.
There will be no evidence of premeditation and they are more likely to leave
evidence such as blood, semen, murder weapon etc. behind.
This type of offender is thought to be less socially competent and more likely to
be unemployed.
Creating a profile: Top-down Typology
In 1992, Douglas et al. introduced a 3 rd category called the
‘mixed’ offender who does not easily fit either of the earlier
two typologies.
This might be because there is more than one offender or
unanticipated events may occur during the crime.
Police felt that putting people into organised and disorganised
categories helps to guide their search for the suspects’
behavioural characteristics.
Top Down approach
Read the textbook on the Top Down approach (pg35).
1. Define what is meant by top-down typology?
1. How have Americans used this approach?
2. Briefly outline Ressler et al’s type of fingerprints.
Top Down approach
4. What additional category did Douglas introduce?
http://www.youtube.com/watch?v=SY4iRb1C9cg
Problems with typologies
What is a problem with using interviews from serial killers?
Other difficulties of the top-down typology
Reliability:
Classification of crimes:
EVALUATION: Canter et al (2004) Investigation of
the organised/disorganised theory of serial murder
Is this research reliable?
Is this research valid?
Ecological Validity
Demand characteristics
Evaluation of OFFENDER PROFILING: Top Down
USEFULNESS OF OFFENDER PROFILING (AMERICAN APPROACH)
The American approach is a good guide in helping investigators search for the
suspect’s behavioural characteristics.
Reliability:.
Generalisability:
Validity:
Bottom up approaches
Canter (1990) is the UK’s foremost profiling expert, his bottom-up approach looks
for consistencies in offender’s behaviour during the crime.
The main idea is to identify associations between aspects of the offender’s
characteristics and offence behaviour.
This is a cognitive social approach in which the criminal’s interactions with others
are seen as the key to their behaviour.
No initial assumptions are made about the offender until a statistical analysis
using correlational techniques has been carried out on the detail of the cases. It
relies heavily on computer databases being accurate and powerful.
It can be the little details that are often overlooked that can be crucial to the
success of a case.
Canter’s methods can be seen as more objective and reliable than top-down
procedures because they are always based on data analysis.
Bottom-up approaches
Canter criticised the technique used in the American approach (top down).
He suggests that interviews with criminals are unreliable as the criminals can be
manipulative and they are often disturbed sensation seekers.
He believes that criminals, like most people behave consistently, so criminals will
reflect their normal behaviour patterns when they commit crime, which leads to
further clues.
An analysis of the pattern of behaviour observed over a number of crimes
committed by a serial offender will give clues about the non-offending everyday
behaviour of the criminal.
The British approach (bottom up) involves advising police officers about
correlations between sets of data, such as time, place, choice of victim.
British Approach
Interpersonal Consistency
Spatial Consistency
The behaviour of the offender at
the time of the crime will be
comparable to what they’re like
in every day life
Marauders
Degree of violence used in
serious crimes, especially rape,
may reflect how the criminal
treats other women in his noncriminal life
• Commit their crimes close to where
they live or feel secure.
• Usually disorganised criminals
Commuters
• Commit their crimes away from
where they usually live
• Usually organised
Canter & Heritage
They have built up their own typologies and have grouped criminals in three ways,
each giving a clue to the offender:
Victim as person – involving conversation during the attack. This type of offender
believes he is developing some type of relationship with the victim, and
mistakenly believes, the sexual assault produces intimacy.
Victim as object – blindfolding/gagging the victim, while the offender tends to be
disguised. The offender is concerned most with control in the interaction of the
rape.
Victim as vehicle – violence (both physical & verbal), which demeans the victim.
The actions here are a reflection of the offender’s anger.
Bottom Up Approach
Read the textbook on the Bottom Up approach (36).
1.
Define the Bottom Up Approach.
1.
Briefly outline how profilers such as Canter, collect their data ?
2.
What are the strengths and limitations of collecting data about criminals in
this way?
EVALUATION of Canter & Heritage: Bottom Up
Approach
Correlation:
Reliability:
Validity:
Deterministic:
How does the Canter and
Heritage Study Illustrate the
Bottom Up Approach?
Profiling Case Study
The case study is based on the account by Canter of the profiling of the “Railway
Rapist”.
Canter became involved in the case in January 1986 when he bought a copy of the
Evening Standard to read on the train.
The front page contained details of a series of 24 sexual assaults that had taken
place in London over the previous four years
All the assaults were assumed to be by the same man, sometimes working alone
sometimes with another person
Key Study – the Railway Rapist (1994)
Canter made 2 assumptions in analysing the case
1.
That people influence each others actions (social psychology) and that any
differences in the attacks involving one man and the attacks involving two,
might offer clues
2.
Peoples behaviour changes over time (developmental psychology) and that
looking at the differences in crimes over the 4 year period might offer
further clues.
3.
He drew up a chart and attempted to see if there was a pattern to the rapes.
Case-study: Canter – John Duffy –
The Railway Rapist
The most famous case carried out by Canter is that of the ‘Railway Rapist’,
John Duffy (using British approach).
Summarise his case-study below
Case-study: Canter – John Duffy –
The Railway Rapist
Evaluation of John Duffy’s case
(uses Canter’s methods – bottom up approach)
Generalisability:
Case-study:
Ecological Validity:
Exam Practice question
a) Describe one approach to offender profiling.
(10 marks)
b) Assess the effectiveness of offender profiling.
(15 marks)