bottom up approach

• what is the bottom up approach?

  a data driven approach where statistical techniques are used to make predictions about the likely characteristics of an offender
• stages of Investigative psychology- David canter?

  • Interpersonal coherence = looking for correlations in offenders behaviour eg sign of shy/aggressive
  • forensic awareness - Certain behaviour reveal offenders awareness of police techniques eg davis found rapist who conceal fingerprints often had a previous burglary conviction
  • Small space analysis- statistical technique by canter where data about crime scene and offender characteristics are correlated and analysed for common connections and come up with themes 
•  Main three themes they identified were?

  • Instrumental opportunistic -’instrumental’= murder to attain  or accomplish something, murderer took easiest opportunities
  • Instrumental cognitive- more planned -concern of being detected 
  • Expressive impulsive- uncontrolled, in the heat of strong emotions, fell provoked by victim 
• what does the bottom up approach look for?

  consistencies in the offenders behaviour during the crime
• Canter used these methods with Duffy who was known as the railway rapist, he committed 24 sexual assualts over 4 years

  He analysed geographical information from similar crime scenes with using bottom up techniques to draw up a very accurate profile.
• what is geographical profiling?

  Geographical profiling is a form of bottom up profiling based on location or locations of a series of crimes, it analyses spatial relationships between scenes and how they might reveal an offender’s place of residence
• What is circle theory?


  • It proposes two models of offender behavaiour, people operate within a limited spatial mindset that creates imagined boundaries in which crimes are likely to be committed
• who are Marauders?


   

  The offender operates in close proximity to their home base
• what are Commuters?

  • the offender is likely to have travelled a distance away from their usual residence
• what is Criminal geographical targeting?

  A computerised system by rossmo, creates a 3d mapn  with spatial data relating to  time distance and movement to and fromcrime scenes. This map is called a jeopardy surface