Making a Case

Interviewing witnesses, Interviewing suspects, Creating a profile

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  • Created by: Laura
  • Created on: 17-06-11 08:38

Interviewing Witnesses

Recognising and

Recreating Faces


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Interviewing Witnesses

We are better at recognising external features (hair, shape of face etc) of a face than the internal features (eyes, nose, mouth)


  • 30 staff and students
  • 3 conditions - external features, internal features and complete face
  • There was no significant difference in accuracy between complete group and external group
  • Internal features only correct 19% of time (as opposed to 35%)

Although accuracy of recognition is not great with external features, it is significantly better than internal features which suggests when witnesses are recalling internal features, we may not be able to rely on their accounts as much.

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Interviewing Witnesses


Weapons Effect

Loftus & Messo

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Interviewing Witnesses

Weapons effect - people are more likely to take notice of faces if the offender doesn't have a weapon


  • Group 1 shown clip of person handing cashier a cheque. Group 2 person pulling out a gun
  • No significant difference in recall of information
  • Gun group only selected correct offender 11% of time, cheque group 39%
  • Gun group longer eye fixation on gun then p's looking at cheque

Weapon focus can negatively affect accurate identification of the offender as our brain automatically focuses us on the most dramatic visual images

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Interviewing Witnesses


Cognitive Interview Technique

Fisher et al

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Interviewing Witnesses

CIT relies on process of guided retrieval and acourages and assists the witness to access all the appropriate info. 4 main techniques:

  • Recreating context - asks witness how they were feeling before and during event
  • Focused concentration - persuade witness to concentrate hard on task and focus on all sensory details, even those considered irrelevant
  • Multiple retrieval - encourage witness who feels they've recalled everything to try again
  • Varied retrieval - asks witness to recall things in different order

Results showed CIT produced 63% more info and this corroborated 94% of the time

This suggests not only does CIT produce more info, it is not at expense of accuracy and so all police should be trained in this technique

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Interviewin Suspects


Detecting Lies

Virj and Mann

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Interviewing Suspects

Research into ability of police officers to detect deception

  • 52 police officers (26 female, 26 male)
  • Officers had to watch videos then indicate whether they thought person was lying, how confident they were with their decision, whether they could understand person, any behavioural cues prompting decision
  • 3 officers right 80% of time
  • 45/52 officers right average 50% time implying they'd have done no better had they been guessing

Detecting deception is very difficult

Age, length of service and experience had no effect on accuracy BUT males better than females.

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Interviewing Suspects


Interrogation Techniques

Darelle Exener case

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Interviewing Suspects

'Reid' approach - relies heavily on presenting damaging facts to persuade suspects to confess & felt it justifiable for police to lie or use tricks to force confession


  • Direct confrontation
  • Offering chance to shift blame
  • Not allowing suspect to deny guilt
  • Giving two choices as to why they may have committed offence
  • Getting them to admit guilt in front of witness & sign confession

Used in case of Darelle Exener - 3 suspects confessed but later found out to be false confessions when real offender owned up

Good at getting confessions but often FALSE confessions - suspects then sent to prison and then their lives ruined. NOT ETHICAL

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Interviewing Suspects


False Confessions


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Interviewing Suspects

3 different types of false confession:

  • Voluntary - offered without external pressure
  • Coerced Compliant - suspect confesses to escape stressful situation
  • Coerced Internalised - suspect temporarily persuaded of their guilt

Experiment - the ALT key:

  • Split into 4 groups - highly vulnerable, highly vulnerable & evidence, low vulverable and low vulnerable & evidence
  • In evidence condition, witness gave (false) incriminating evidence and in HV words read faster
  • LV & no evidence least likely to comply and HV & evidence most likely to confess
  • HV & evidence - 65% internalised ('i must have hit wrong button')
  • Presence of witness statement alone can induce false confession and also mild state of stress
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Creating a Profile


Offender Profiling

American Approach - Top Down

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Creating a Profile

Offender profiling - developing an idea of suspect based of characterisitcs of offence

36 convicted sexually orientated murderers

Classification system based on characteristics of murderer - organised or disorganised

Organised Murder & Murderer

  • Crime is planned & shows self-control
  • Leaves few clues & attempts to control victim who is a stranger
  • Above ave. IQ
  • Socially/sexually competent - married/cohabiting
  • Skilled occupation
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Creating a Profile


Offender Profiling

American Approach - Top Down

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Creating a Profile

Disorganised Murder & Murderer

  • Little planning/prep & little attempt to hide evidence
  • Minimum use of constraint
  • Random and disorganised
  • Lives alone & socially/sexually inadequate
  • Unskilled occupation
  • Abused in childhood


  • reductionist as classifies as either one or other so might rule out someone who is offender because they don't fit profile
  • only based on sexually orientated murderers so can't generalise to other crimes
  • limited sample
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Creating a Profile


Offender Profiling

British Approach - Bottom Up

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Creating a Profile

Canter - More scientific, looks at how crime mirrors offender's everyday life (criminal constistency hypothesis)

Interpersonal consistency - interactions between victim and offender

e.g. offender who warns victim not to go to police/destorys evidence will have knowledge of police procedure OR **** with low level sexual contact offender will have low level sexual activity in other areas of life and will live alone

Spatial consistency - geographical area in which they commit the crime

Marauders (crime committed close to home so has local knowledge) and Commuters (travels away from home to commit crime)

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Creating a Profile


Offender Profiling

British Approach applied

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Creating a Profile

John Duffy (Railway ******)

Canter looked at behaviour shown in each **** and used criminal consistency hypothesis to develop a profile for the suspect:

  • he lived in the area of the first 3 ****s
  • Lives with wife/girlfriend
  • Mid to late 20s
  • Semi-skilled job with knowledge of railway system
  • Sexually experienced and fantasises about **** and *******

The profile was very accurate and led to arrest of John Duffy

Study by Copson found that whilst 50% of police officers questioned found profiling provided something extra, only 14% felt it helped solve the case

BUT it only led to ID of offender in less than 3% of cases

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