Bottom-Up

• A data-driven methodology that doesn't assume there are existing categories of offenders

  Relies on statistical analysis, evidence and psychological theory to make inferences about linked crimes and offender

  the dominant British approach developed by David Canter
• Investigative psychology

  An attempt to apply statistical procedures, alongside psychological theory, to the analysis of crime scene and evidence
• Investigative psychology

  Aim is to establish patterns of behaviour that are likely to occur, or co-exist across crime scenes

  This is done in order to to develop a statistical database which then acts a s a baseline for comparison
• Investigative psychology

  Specific details of an offence, or related offences, can then be matched against this database to reveal important details about the offender, their personal history, background, etc

  This may also determine whether a series of offenders are linked in that they are likely to have been committed by the same person
• Interpersonal coherence 


  The way the offender behaves at the scene, including how they ‘interact’ with the victim, may reflect their behaviour in more everyday situations

  For example, whilst some rapists want to maintain maximum control and humiliate their victims, others are more apologetic (Dwyer 2001)

  this might tell the police something about how the offender relates to women more generally
• Time and Place


  The significance of time and place is also a key variable and may indicate where the offender is living
• Forensic awareness 


  Describes those individuals who have been subject of police interrogation before, their behaviour may denote how mindful they are of covering their tracks
• Crime Mapping 


  Uses information to do with the location of linked crime scenes to make inferences about the likely home or operational base of an offender

  Can be used in conjunction with psychological theory to create hypotheses about how the offender is thinking as well as their modus operandi
• Geographical profiling

  The assumption is that the serial offender will restrict their ‘work’ to geographical areas they are familiar with, and so understanding the spatial pattern of their behaviour provides investigators with a ’centre of gravity’ which is likely to include offenders base

  It may also help investigators make educated guesses about where the offender is likely to strike near - Jeopardy Surface
• Circle theory (Canter and Larkin 1993)


  Proposed two models of offender behaviour:

  • The Marauder
  • The Commuter

  The pattern of offending is likely to form a circle around their usual residence, and this becomes more apparent the more offences there are

  Spatial decision making can offer the investigative team important insight to the nature of the offence (eg planned or opportunistic), as well as real revealing other important factors about the offender, such as their mental maps, mode of transport, employment status, approximate age, etc
• The Marauder


  Operates in close proximity to their home base
• The Commuter 


  Likely to have travelled a distance away from their usual residence
• Strength - Good application to a range of crimes

  Can be applied to a wide range of offences

  Techniques such as smallest space analysis and the principle of spatial consistency can be used in the investigation of crimes such as burglary and theft, as well as more serious offences like murder and rape
• Strength - Evidence

  Canter assisted police in tracking down the Railway Rapist (John Duffy) - he analysed geographical information from the crime scenes and combined this with details of similar attacks in the past

  Carter drew up a profile of Duffy which was surprisingly accurate and led to his arrest and conviction

  EG, profiled him to live in Kilburn, do martial arts, have marriage problems, fantasies or rape and bondage, etc
• Weakness - Evidence

  Rachel Nickell was murdered in front of her child in 1992

  A profile of offender was developed by Paul Britton

  Police received tip offs that Colin Stagg was the murderer

  Undercover police officer befriended Stagg to get him to confess

  Stagg didnt confess but was still arrested

  Judges threw out the case as there was no evidence of Stagg‘s involvement

  Over 15 years later, Robert Napier, who was initially too tall to be the suspect admitted to the crime
• Strength - Scientific / objective

  Grounded in evidence and psychological theory, and less driven by speculation and hunches - therefore more scientific than top down approach

  With the aid of advanced AI, investigators are able to manipulate geographical, biological and psychological data quickly to produce insights and results that assist in investigation