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Creating a Profile.

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Presentation on theme: "Creating a Profile."— Presentation transcript:

1 Creating a Profile

2 Like a Jigsaw See the picture then find the pieces to fit it
Top Down Typology MEXICO USA CANADA Like a Jigsaw See the picture then find the pieces to fit it

3 Top – Down Typology

4 Top – Down Typology The American, or ‘top-down’, approach was compiled by the FBI through a series of in-depth interviews with 36 convicted sexually orientated murderers, including Ted Bundy and Charles Manson. This information, along with detailed information from the FBI Behavioural science unit, was combined with detailed examination of the crime scene, the nature of attacks, forensic evidence, and any information relating to the victim to develop models that would result in a profile of the offender. From this the FBI developed a classification system for several serious crimes. Murders (in particular ‘lust murders’) were classified as either ‘organised’ or ‘disorganised’ and a set of characteristics was built from this. Organised offenders would show planning in their crimes, leave few clues, and target a stranger; from this it was possible to infer that they would be above average IQ, be socially and sexually competent and in a skilled occupation. Those categorised as disorganised would show the opposite traits.

5 Organised murder scene
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. Organised murder scene Planned Victim — targeted stranger Control including restraints, Aggression before death Body hidden or moved from crime scene Weapon and evidence absent Disorganised scene Spontaneous Victim — known by offender Little control Sexual acts before death Body not hidden or left at crime scene. Evidence present Organised murderer More-than-average lQ Skilled occupation Controlled mood Living with partner Mobile — for example, car Socially competent Sexually competent Inconsistent discipline as child Use of alcohol during crime Follows crime on news Limited change in behaviour after crime Disorganised murderer Less-than-average IQ Unskilled Uncontrolled Living alone Lives near crime Socially incompetent Sexually incompetent Harsh discipline as child Alcohol not used during crime Does not follow crime on news Major behaviour change after crime

6 FBI The FBI need certain information before they can make the profile
Colour Photos of the crime scene Data about the neighbourhood of the crime (housing, income) Medical Examiners report A map of the victims travels prior to death A complete investigative report of the incident Background details of the victim

7 FBI – 4 STAGES DATA ASSIMILATION CRIME CLASSIFICATION
CRIME RECONSTRUCTION PROFILE GENERATION

8 Agents Given the evidence provided your task is to draw up a profile of the offender. Use the the differences between organised and disorganised murders

9 The following exercise is taken from Howitt (2002) and is based on a case originally reported by Ressler et al (1988). A nude female's body is was found at 3.00pm on the roof of an apartment block where she lived. She had left home for work at 6.30 in the morning. She was 26 years of age, 90 lbs in weight, her spine was deformed and she was not dating men. Both of her nipples had been removed and placed upon her body. Her face was severely beaten. She had been throttled with the strap of her bag. A blunt instrument had caused many face injuries. Virtually all items used came from the victim’s bag. The phrase "You can't stop me" was written in ink on the inner thigh and "Fuck you" on the torso. The pendant she usually wore was missing. The victim’s underwear had been taken down and pulled over her face. Her stockings were tied around her ankles and wrists but very loosely. A pen and an umbrella were inserted into her vagina. A comb was stuck in her pubic hair. There was no semen in the victim’s vagina. The offender had ejaculated over her body from a standing position. There were bite marks on her thighs and various bruises/lacerations all over. Faeces from the murderer were very close by. They were covered with the victim’s clothes. There was no evidence of similar crimes being carried out in the area.

10 So Agents……. Give me your profile of the offender!

11 What the FBI have to say…
A white man. Aged between 25 and 35 years - similar in age to the victim. Sexual fantasies have been harboured by the offender for a long time and possibly uses and collects sadistic pornography. He would fit into the context well - might reside in the apartment block or work there. Average intelligence but dropped out of education. No military background. Possibly unemployed. Unskilled or skilled occupation. Alcohol and drugs would not have materially contributed. Difficulties in personal relationships with women. Any dates would be younger so that they could be more easily controlled and dominated. Sexually inexperienced and inadequate. Never married. Disorganised offender - confused and perhaps mental difficulties in the past. Messages challenged the police and may indicate future killings.

12 Additional Info - FBI Killers tend to be similar in terms of age and race to their victim. Fantasy is at the core of extreme cases like this. The fantasy may involve the thinking about and planning for the offence. The sadistic nature of the crime is probably indicative of the offender's fantasy. Keeping a trophy, the pendant, will help the offender fantasise about this in the future. Although the offender fantasised and "planned" the murder in his fantasy world, there was little evidence of real planning. This was a disorganised crime, the offender using what came to hand in the course of the crime....her pen, her umbrella etc. The crime was sexual but there was no penetration by the offender, only the substitutes. It is this that suggests sexual inadequacies and the likelihood that he lacked sexual experience and had never married. The victim was partially disabled, she was tied up in a crude way, and this suggests the offence has elements of control and domination. Defecation near a crime scene is not unusual but in this case it perhaps indicates that the offence took place over a lengthy period of time. Potentially, this represents a considerable risk for the offender since he was in an exposed situation (a roof top). Unless of course he lived or worked in the area and knew he was unlikely to be disturbed.

13 The killer…. Using this profile the police were able to work through their records and identify a man whose father lived in the same apartment block. The police had been told that his son was in a mental hospital but they found that security there was poor. The crucial piece of evidence was the bite marks on the body which matched the dental pattern of the suspect.

14 What’s wrong with this approach?

15 Discuss briefly and I will go through it at the end…

16 Canter 2004 – serial murder and investigation (to be researched for Wednesday!)

17 Bottom-up/Geographical Offender Profiling
The British Way

18 Bottom up approaches Canter 1990 – UK’s foremost profiling expert, his bottom up approach looks for consistencies in offenders behaviour during the crime. No initial assumptions are made about the offender. Relies heavily on computer databases.

19 The British, or ‘bottom-up’, approach is more scientific than the American approach in that it uses more psychological theories and methodologies. Seen as a cognitive social approach and looks at associations between the offenders characteristics and the offence behaviour. This approach looks for ways in which the crime might mirror the behaviour of the offender in every day life – the Criminal Consistency Hypothesis (Canter (1989)). This consistency principle has been applied to two areas: interactions between the victim and the offender (interpersonal consistency); and the geographical area in which the criminal commits the offence (spatial consistency). Within interpersonal consistency it is argued, for example, that the degree of violence used in serious crimes, especially rape, may reflect how the criminal treats other women in his non-criminal life. Spatial consistency is based on the idea of mental maps; criminals then draw on these mental maps when committing a crime (so committing a crime somewhere they are comfortable with, on the way to a friends or work). Two types of offenders were highlighted: the marauders who use a fixed base (usually home) and offend around that central point (as little as 2 miles, Canter & Gregory, 1994) ; or commuters who travel far to the location of the crime to disassociate themselves from the geographic location.

20 Called bottom-up as no initial assumption is made about the offender until a statistical analysis using correlational techniques is carried out. Relies heavily on computer databases being accurate (more objective and reliable than the American approach). 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.

21 Evaluation points?

22 Strengths Trying to build a ‘picture’ of the person who committed a crime without ever having contact with them. It helps to narrow down the scope of people from where to start looking for suspects – helps focus police resources. It can establish description of likely social, physical and mental characteristics. This can help establish where and when they are likely to offend again and possible victims. This can lead to possible interview strategies to elicit confession of guilt or details of a crime. Can reduce list of potential suspects Could force a slip-up to enable detection

23 Weaknesses Police resources have been wasted pursuing the wrong person
Can be an over-reliance on so-called ‘expert’ without acknowledging the invaluable contribution of experienced police officers Small percentage of successes in catching offender when working with offender profiling

24 Evaluation extended: An initial problem with research into offender profiling lies in the researchers only focusing on one variable that could be the cause an offender committing a crime; this is known as being reductionist. For example, the American approach uses topologies to categorise offenders as either organised or disorganised. Some offenders could show characteristics of both topologies. In contrast, the British approach uses a variety of psychological theories to provide an understanding of how an offenders’ behaviour during an offence relates to their everyday life therefore allowing for many more variables to be taken into account and thus not being reductionist. Research which is reductionist is problematic as it doesn’t look at the entire range of influences on behaviour and we may get a distorted picture of the behaviour being investigated.

25 Evaluation The research presented in this area has many useful applications to the real world. We are able to use the results to predict why some criminals offend, and also design strategies to intercept and catch offenders. For example, the American approach allows psychologists to classify offenders as one of the two topologies, and as a result provides certain personal characteristics about the offender which could allow police to target their enquiries more efficiently. Similarly, the British approach has proved it’s usefulness through applications such as the John Duffy case (Canter (1994)). This case provided strong support for using the criminal consistency hypothesis to create a profile of the offender and the profound effects a profile can have on apprehending an offender.

26 Timed Essay a) Describe the bottom-up approach to creating a profile
b) Assess the reliability of offender profiling January 2010 a) Describe one case study as an approach to offender profiling. b) Compare different approaches to creating a profile. January 2011

27 Exam Questions:

28 January 2010 (a) Describe the bottom up approach to creating a profile. [10] (b) Assess the reliability of offender profiling. [15]

29 January 2010 (a) Describe the bottom up approach to creating a profile. [10] - Offender profiling is commonly used in crimes such as paedophilia, rape, murder as well as satanic and ritualistic crime. There are two types of offender profiling: the ‘top-down’ approach which the American profilers use and the ‘bottom-up’ approach which is used in the UK. The ‘bottom-up' approach takes the evidence and data and builds up a pattern piece by piece until a feasible conclusion is reached. It seeks out consistencies in offender behaviour, usually from the crime scene and victims’ accounts. David Canter is one of Britain’s foremost profiling experts, such as his work with former detective constable Rupert Heritage on developments in offender profiling.

30 (a) Describe the bottom up approach to creating a profile
(a) Describe the bottom up approach to creating a profile. [10] - examiners report The bottom-up approach was sometimes well described but all too often candidates merely described the John Duffy case study at length. Occasional confusion with Top/Bottom/US/UK approach. Too few candidates could explain how the bottom up approach created a profile and simply stated aspects of Canter's theory on profiling without showing how this is then used to generate a profile.

31 January 2010 (b) Assess the reliability of offender profiling. [15]
- Reliability refers to the consistency that exists in the data, whether all things being equal the same test would produce the same findings at another time, or whether two or more researchers (observers) would record the same data. So in terms of creating a profile, would any two profilers produce the same profile, and hence suspect, given the same information or would their different interpretations colour the suggested outcome? Could other factors confound the outcome, particularly cognitive factors such as those suggested by Loftus? No more than attempting to address the question or a highly superficial response would constitute an answer in the bottom (1-3) band. This improves to a more accurate if somewhat limited response; a more detailed or broader response; and at the top level a more developed and/or elaborated response containing more precise evaluative points and/or issues. For example, specifying inter-rater reliability or test-retest reliability, or breaking ‘reliability’ per se into demand characteristics, social desirability, accuracy due to other factors would all suggest a better quality of response.

32 (b) Assess the reliability of offender profiling. [15] Examiners report
Many candidates were vague about the meaning of 'reliability' or did not distinguish between reliability and validity. Those that did could not relate the concept well to profiling. Much credit was serendipitous, relating biases to reliability when this point was not made explicitly. Reliability caused many problems in this question as many seemed unable to apply it to how a profile is used or created.

33 June 2010 no questions

34 January 2011 A) Describe one case study as an approach to offender profiling. [10] B) Compare different approaches to creating a profile. [15]

35 January 2011 A) Describe one case study as an approach to offender profiling. [10] - The case study of John Duffy represents an approach to profiling as adopted by David Canter. Similarly, his methods have been developed, such as geographical profiling suggested by Dr. Kim Rossmo. Weaker responses may simply report some of the details of a case study, better responses will present these as part of the case study as an approach to criminal investigation.

36 Describe one case study as an approach to offender profiling
Describe one case study as an approach to offender profiling. [10] Examiners report The least popular question in this section. Almost every answer used the Canter/ Duffy case to answer this question. The best answers explicitly related the approach to the case study giving examples of how Canter used the Duffy case. Examples included small space analysis, geographical profiling etc. Weaker answers simply described the case study.

37 January 2011 B) Compare different approaches to creating a profile. [15] - Different approaches could be top-down and bottom up, American and British (FBI and Canter), profilers such as Canter and Rossmo. Responses could be a comparison of approach, a factual comparison, a comparison of methodology or a comparison of a particular issue between two approaches. Note that comparisons can be both similarities and differences.

38 B) Compare different approaches to creating a profile
B) Compare different approaches to creating a profile. [15] Examiners report Most candidates offered some evaluation. Candidates mentioned both approaches although differences were less well identified. The more able candidates were able to compare and contrast and mention evaluative aspects such as the differing methodologies. The better answers drew clear points of comparison between the two approaches such as reliability, reductionism, generalisability and so on. Weaker answers tended to simply describe the two approaches side by side.

39 June 2011 – no quesiton

40 January 2012 – no quesiton

41 June 2012 Describe how top down typology is used to create a profile. [10] Assess the usefulness of qualitative and quantitative data when creating a profile. [15]

42 June 2012 Describe how top down typology is used to create a profile. [10] ‘Top-down’ is traditionally the American approach. It proposes a hypothetical overview onto a crime scene which is referred to as a typology. The details in the scene will be considered within this framework to see if they support the hypothesis. Common patterns in murder scenes help them to be categorised as either organised or disorganised. Research may enhance the quality of response, but is not a pre-requisite for full credit which could also be achieved by an explanation of the FBI’s use of Top-down typology, for example. Contextualising and thoroughly explaining the use will typify the better response, whereas a failure to do this will result in a weaker accreditation. Better candidates will not only describe the top-down typology but address ‘how’ it can be used to create a profile. Weaker candidates may merely describe some components of top-down typology but not address the ‘how’.

43 Describe how top down typology is used to create a profile
Describe how top down typology is used to create a profile. [10] Examiners report There were many good responses to this question. These candidates not only referred to ‘the bigger picture’, but described what this means in terms of profiling. Some candidates’ descriptions were confused or unclear. Some lacked detail; others were anecdotal and often not obviously top-down topology.

44 June 2012 Assess the usefulness of qualitative and quantitative data when creating a profile. [15] Candidates should assess the usefulness of qualitative and quantitative data when creating a profile. When creating a profile, data collected can be empirical ie quantitative or more descriptive ie it is possible to consider strengths and weaknesses of the approaches as well as in terms of evaluative issues. For example, the depth and richness of data is superior in the qualitative approach. Quantitative data is easier to record, easier and clearer to analyse and more objective. It may lead to a more accurate profile due to exclusion of cognitive interference such as selection, distortion and bias, for example. The bottom up is arguably particularly quantitative, looking for patterns in data. The top down approach moves towards a more qualitative approach, its methods reflecting this.

45 Assess the usefulness of qualitative and quantitative data when creating a profile. [15] Examiners report Most candidates knew what qualitative and quantitative meant, better candidates were able to consider how they are more or less useful when creating a profile.

46 January 2013 – no question

47 June 2013 – no question

48 June 2014 – Don’t think it did!

49 Studies and case study

50 Interviewing witnesses, suspects and creating a profile.
Making a case Interviewing witnesses, suspects and creating a profile.

51 How can we apply the approaches?
Behaviourist Assumes that all behaviour is learned, either through association or through reinforcement. They will look for habitual patterns in a criminals’ behaviour and exploit the power of association or reward when trying to get people to speak up. Cognitive The development of techniques to trigger memories, spot liars and understand criminal thinking patterns have been beneficial to forensic psychology. Individual differences Understanding that everyone’s memory of sense of guilt works in different ways.

52 Theories of creating a profile
Canter et al, Canter and Heritage, Canter

53 Theories of creating a profile.
Profiling is one of the many techniques used to solve crimes, particularly when dealing with unusual or serial crimes. Profiling attempts to categorise offenders based upon their unusual criminal activity patterns, thought patterns and the environment in which they commit their offences. The main approaches within this section are individual differences, cognitive and social.

54 Top-down approaches: A top-down approach tries to fit everything into a set of pre-designed categories. A good example is astrology and the zodiac. This top-down approach to predicting someone's future is because of identifying a small piece of information about the person, their birthday, and fitting them into an astrological type, this making all sorts of predictions about the individual including their personality.

55 Top-down approaches in profiling:
Top-down approaches exist in criminal profiling. Profilers have created typologies of criminals. A typology s a set of clear and distinct categories. When investigators arrive at the scene, they are looking for clues that reveal what type of criminal was there. Sometimes the clues may point to more than one typology so investigators try to go for the ‘best fit’. Once the type has been identified, investigators can make predictions about whether the criminal will strike again, where, and who the victim might be.

56 Bottom-up approaches:
Bottom-up approaches make no assumptions about the person or object they are dealing with. Instead, a researcher will gather together all the information then build up a logical description based on that. A bottom-up approach could be something like a tarot card reading where all the chosen cards meanings are put together to make a whole prediction.

57 Bottom-up approaches in profiling:
The bottom-up approach is popular in Britain and is championed by David Canter. Canter started out as an environmental psychologist, looking at how people’s behaviour in buildings stayed the same, even in emergencies such as a fire. From this, he developed his criminal consistency hypothesis which states that an offenders behaviour while committing a crime will be consistent with their behaviour in their daily life.

58 Investigation of the organised vs disorganised theory of serial murder
Canter et al 2004 Investigation of the organised vs disorganised theory of serial murder

59 Background: Disorganised
In 1980, Hazelwood and Douglas published their account of the ‘lust murderer’ whereby they outlined their theory that lust murders can be categorised as organised or disorganised. Organised Leads an ordered life Sexually competent Social competent Kills after a critical life event Premeditated Planned crimes Bring weapons which are removed from the scene Use restraints for control Average intelligence Employed in skilled jobs Body is hidden or removed from the scene. Disorganised Committed the crime in a moment of passion Spontaneous No evidence of premeditation Leave evidence- blood, semen, weapons Body may be left and unhidden Less socially competent Less sexually competent Unemployed or in unskilled work Less than average intelligence Lives alone.

60 Aim: To test the reliability of the top-down typology by applying them to 100 cases.

61 Procedure: A content analysis of 100 cases of serial killers from the USA in order to see if the features hypothesised to belong to each typology would be consistently and distinctively different. The cases came from published accounts of serial killers and were cross-checked with court reports and officers where possible. They had been collected over several years by an independent researcher and were called the Missen Corpus. The third crime committed by each serial killer was analysed using the Crime Classification Manuel in order to determine the crime as being organised or disorganised.

62 Findings: Twice as many disorganised crimes as organised crimes were identified, suggesting that disorganised offenders are more common or easier to identify. Two behaviours in the organised typology occurred a level significantly above chance. In 70% of cases, he body was concealed In 75% of cases, sexual activity had occurred. Further analysis failed to reveal any significant differences between organised and disorganised variables.

63 Conclusions: Canter concluded that instead of their being a distinction between the two types of serial murderer, all of the crimes had to have an organised element to them. We might expect this as they were not caught after three killings! The distinction between serial killers may be a function of the different ways in which they exhibit disorganised aspects in their activities. It would be better to look at personality differences between offenders.

64 Issues: Usefulness Reliability Validity
Can be applied to identifying a murderer Reliability Had an dependent researcher Tested against the CCM Validity Used real-life murder cases

65 Debates: Ethnocentrism Reductionism vs Holism
All cases were from the USA giving very westernised views of murderers Reductionism vs Holism R: Top-down approach forces people into categories in which they do not fit. H: Looks at social factors as well as environmental factors- employment, etc.

66 Developments in offender profiling
Canter and Heritage 1990 Developments in offender profiling

67 Background: Canter’s bottom-up approach looks for consistencies in the offenders behaviour during the crime. These can be inferred from the crime scene, or from surviving victims accounts. No initial assumption is made about the offender until a statistical analysis using correlational techniques has been carried out on the details of the cases, The approach relies heavily on computer databases being accurate. This approach can be considered more objective and reliable.

68 What factors can affect the accuracy of police records?
Think… This approach relies heavily on data held in computer databases and this data being accurate. What factors can affect the accuracy of police records? Not all crimes are followed up Eye-witness Testimony? Data being lost? Anomalous results? Leading questions? Not all crimes are reported? Human error?

69 Aim: To identify a behaviour pattern from similarities between offences.

70 Procedure: A content analysis was carried out on 66 sexual offences from various police forces committed by 27 offenders to find 33 offence variables that were clearly linked to a potential behaviour characteristic. It was possible to say yes or no to each variable. A computer was used to work out the correlations between each aspect of the crime and identify the key factors central to sexual assault. This method is known as a smallest-space analysis, because it presents results visually, with the most common factors closer to the centre and less typical behaviours appearing out on the edges.

71 Smallest-space analysis example:
Behaviour occurs in 40-60% of cases Behaviour occurs in more than 65% of cases Behaviour occurs in 25-35% of cases Behaviour occurs in 20-25% of cases

72 Findings: Five variables were found to be central to the 66 cases;
Vaginal intercourse No reaction to the victim Impersonal language Surprise attack Victims clothing was disturbed This suggests a pattern of behaviour where the attack is impersonal and sudden and the victim’s response is irrelevant to the offender.

73 Conclusions: This has become known as the five factor theory.
These five aspects have now been shown to contribute to all sexual offences, but in different patterns for different individuals. An analysis of these factors can enable police to decide if an offence has been committed by the same individual.

74 Issues: Correlational methods Reliability Application
Does not show cause and effect Reliability The accuracy of the police databases as described earlier Application Can work to help stop crimes and identify the criminals Quantitative data Objective and not influenced by personal opinions

75 The case of John Duffy the ‘Railway Rapist’
Canter The case of John Duffy the ‘Railway Rapist’

76 Background: In November 2000, John Duffy, who was serving life for the rape and murder of several women, confessed to his prison psychologist that in fact he was responsible for many more cases and that he had committed many of these acts with an accomplice- David Mulcahy. He therefore testified in front of the jury at Mulcahy’s trial, giving evidence to ‘clear his conscience’.

77 Background: In 1982, a woman- KJ- was raped near London’s Hampstead station and dozens more were attacked over the next 2 years. The police set up a workshop to find the perpetrators, called Operation Hart. The press called the attacker the ‘Railway Rapist’ but this changed to the ‘Railway Killer’ in 1985 when Alison Day was dragged off of a train in Hackney and repeatedly raped and strangled with a piece of string. In April, a 15 year old was raped and murdered and her body was set on fire. A month later, a local TV presenter was abducted and murdered after leaving a train in Brookman's Park.

78 Background: The police investigation was getting nowhere, because although the surviving women could give details accounts of the attacker’s methods of working, they were uncertain about his height and appearance. They were possibly distracted by the weapons focus effect.

79 Aim: To show successful application of a “bottom-up” approach of profiling to solving a crime.

80 Procedure: In 1988, Canter was invited by the Metropolitan Police to draw up a profile of the ‘Railway Rapist’. Cater examined the details of each crime and built up a profile of the attacker’s personality, habits and traits. He used the bottom-up approach to identify two significant themes in the attacks; The attacker seemed prepared to try to relate to the victim- suggesting a previous abusive relationship. Minimal amount of force was used to the victim- suggesting a weak, insecure individual.

81 Procedure: Canter also studied the location of the crimes, going back 4 years, laying transparent acetate sheets with the crime scenes marked on top of the map of the area surrounding London. This built up a geographic profile which helped him pin down where the attacker lived because he pattern suggested he was a marauder who committed crimes in his own neighbourhood.

82 The profile: Canter’s profile included that the offender;
Lived in Kilburn or Cricklewood Was married Had no children Had marriage problems Was a loner with few friends Was physically small Had feelings of unattractiveness Has an interest in martial arts or body building Had a need to dominate women Had a fascination with weapons- especially knives Had fantasies about sex and violence Was in a semi-skilled job Had little contact with the public Was aged between 20 and 30 years old.

83 Findings: John Duffy was 1505th on the police’s list of suspects with the right blood group to be the attacker. He as on the police database because of a previous incident where he had threatened his wife at knife point. John Duffy fit the profile Canter had made very closely.

84 Findings: John Duffy; Lived in Kilburn Was married Was infertile
Had separated from his wife Only had 2 male friends Was 5”4 Had acne Was a member of a martial arts club Was violent and often attacked his wife Was a collector of martial arts weapons Was a collector of hard core porn videos Was trained as a British Rail carpenter Was aged 28

85 Findings: John Duffy was reinvestigated as a result of Canter’s profile and was convicted for the two murders and five rapes. Canter had also predicted that the attacker would have a signature- most likely he took ‘souvenirs’ from his victims. John Duffy had a collection of 33 house keys that he had taken from the women he had raped and murdered. Police suspected Duffy’s friend David Mulcahy to be his collaborator, but could not prove this. Mulcahy was a married father of 4 and was eventually convicted in 2001.

86 Conclusions: This case study lends support to Canters bottom- up approach to profiling.

87 Issues: Usefulness Generalisability
Can help with identifying and finding offenders Generalisability A case study with a sample size of 1 cannot be easily generalised.


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