Top Down Approach

• •Offender profiling is a behavioural and analytical tool used when trying to solve crimes. It is intended to help investigators to narrow down the number of likely suspects of crime by predicting the probable characteristics of the unknown criminal(s) e.g. their age, background, occupation etc. using evidence from the crime scene.
• •The top-down approach (also called the typology approach) is when profilers have pre-existing conceptual categories of offenders in their minds. They then use the evidence from the crime to fit into either of these categories to classify the offender as one type or the other.
• •The bottom-up approach is when the profilers look at the evidence from the crime and use these to develop likely hypotheses of what the offender is like using their knowledge of psychological theories.
• Top-down approach

  Also called the typology approach, the FBI approach to profiling
• Top-down approach

  • Based on the idea that offenders have certain signature ways of working (modus operandi) and these generally correlate with a particular set of social and psychological characteristics
  • Profilers have pre-existing conceptual categories of offenders in their minds
• Pre-existing offender categories

  • Organised offenders
  • Disorganised offenders
• Using the top-down approach

  1. Evidence from the crime scene and other details of the crime, victim or context are used to fit into either of the pre-existing categories to categorise the offender as one type or the other

  2. A profile is then constructed of the offender which includes hypotheses about their likely demographic background, habits, physical characteristics, behaviour and beliefs

  3. The description is then used to work out a strategy for the investigation to help to catch the offender
• Top-down approach

  Generally regarded as a more intuitive application of a profiler's prior knowledge – they have a 'feel' for the kind of person who committed the crime
• •The bottom-up approach is the British approach to profiling, most closely associated with David Canter.•It is where a profile of the offender (the likely characteristics, routine behaviour and social background) is generated by making inferences from systematic analysis of evidence at the crime scene using knowledge of psychological theories and statistical analysis.•Therefore, the profile is ‘data-driven’ and emerges as the investigator engages in deeper and more rigorous scrutiny of the offence.
• Examples

  •Investigative psychology••••Geographical profiling
• •This is a form of bottom-up profiling developed by Canter that matches details from the crime with statistical analysis of typical offender behaviour patterns based on psychological theory.
• Crime scene evidence analysis

  • Based on psychological theory and evidence
  • Interpersonal coherence - the way an offender behaves at the scene, including their interactions with the victim may reflect their behaviour in more everyday situations as people are consistent in their behaviour
  • Significance of time and place - these may give indications about where the offender lives
  • Forensic awareness - this focuses on individuals who may have been the subject of police interrogation before; their behaviour may denote how mindful they are of 'covering their tracks'
• Rapists

  • Some seek maximum control and humiliate their victims
  • Others are more apologetic
• Offender has cleaned up the crime scene

  Suggests they have committed a crime before and been through the criminal justice system
• Geographical Profiling

  •This is a form of bottom-up profiling first described by Rossomo (1997) which involves the study of spatial behaviour in relation to crime and offenders.•It is based on the principle of spatial consistency – that an offender’s operational base and possible future offences are revealed by the geographical location of their previous crimes.
• Geographical Profiling

  1. Use location of linked crimes

  2. Use local crime statistics

  3. Use local transport

  4. Use geographical spread of similar crimes

  5. Make inferences about likely home, operational base, workplace and social hangouts of the offender
• Crime mapping

  The process of using the above information to make inferences about the offender
• Assumption about serial killers

  • They will restrict their 'work' to areas they are familiar with
  • Understanding the spatial pattern of their behaviour provides investigators with a 'centre of gravity' which is likely to include the offender's base (often in the centre of the spatial pattern)
• Circle theory proposes two models of offender behaviour. People operate within a limited spatial mind set that creates imagined boundaries in which crimes are likely to be committed (usually forming a circle).  
• The Marauder: the offender operates in close proximity to their home base.
• The Commuters: the offender is likely to have travelled a distance away from their usual residence.