Presentation on theme: "MAKING A CASE Interviewing Witnesses Suspects Creating A Profile"— Presentation transcript:
1 MAKING A CASE Interviewing Witnesses Suspects Creating A Profile Recognising FacesDetecting LiesTop-downTypology (FBI)Factors AffectingIdentificationInterrogationTechniquesBottom-upApproach (Canter)Cognitive InterviewFalse ConfessionsCase Study(Railway Rapist)
2 Offender Profiling http://www.youtube.com/watch?v=LPNvAT tE3vA What is meant by an offender profile?Why do detectives come up with an offender profile?
3 Offender ProfilingThere 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.
4 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.
6 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.
7 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.
8 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 non- social and the disorganised asocial offender should be reflected in the crime scene.
9 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.
10 Creating a profile: Top-down Typology In 1992, Douglas et al. introduced a 3rd 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.
11 Top Down approach Read the textbook on the Top Down approach (pg35). Define what is meant by top-down typology?How have Americans used this approach?Briefly outline Ressler et al’s type of fingerprints.
12 Top Down approach4. What additional category did Douglas introduce?
13 Problems with typologies What is a problem with using interviews from serial killers? Other difficulties of the top-down typology Reliability: Classification of crimes:
14 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
15 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:
16 Bottom up approachesCanter (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.
17 Bottom-up approachesCanter 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.
18 British Approach Interpersonal Consistency The behaviour of the offender at the time of the crime will be comparable to what they’re like in every day lifeDegree of violence used in serious crimes, especially rape, may reflect how the criminal treats other women in his non- criminal lifeSpatial ConsistencyMaraudersCommit their crimes close to where they live or feel secure.Usually disorganised criminalsCommutersCommit their crimes away from where they usually liveUsually organised
19 Canter & HeritageThey 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.
20 Bottom Up Approach Read the textbook on the Bottom Up approach (36). Define the Bottom Up Approach.Briefly outline how profilers such as Canter, collect their data ?What are the strengths and limitations of collecting data about criminals in this way?
21 EVALUATION of Canter & Heritage: Bottom Up Approach Correlation: Reliability: Validity: Deterministic:
22 How does the Canter and Heritage Study Illustrate the Bottom Up Approach?
23 Profiling Case StudyThe 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
24 Key Study – the Railway Rapist (1994) Canter made 2 assumptions in analysing the caseThat people influence each others actions (social psychology) and that any differences in the attacks involving one man and the attacks involving two, might offer cluesPeoples behaviour changes over time (developmental psychology) and that looking at the differences in crimes over the 4 year period might offer further clues.He drew up a chart and attempted to see if there was a pattern to the rapes.
25 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
26 Case-study: Canter – John Duffy – The Railway Rapist
27 Evaluation of John Duffy’s case (uses Canter’s methods – bottom up approach) Generalisability: Case-study: Ecological Validity:
28 Exam Practice question a) Describe one approach to offender profiling. (10 marks) b) Assess the effectiveness of offender profiling. (15 marks)