Bottom-up approach

Question 1

What are the principles and origins of the bottom-up approach?

Answer 1

• Developed in Britain by David Canter in the late 1980’s
• No fixed typology - Do not enter crime scene with classification in mind
• Profile of offender is data driven
• E.G. John Duffy – the railway rapist, Robert Napper
  Bottom( look at details from crime scene and similar crimes) -> Up (Hypotheses about characteristics of criminal)

Question 2

Outline investigative psychology.

Answer 2

1. Investigative Psychology
   Applies statistical procedures to analyse crime scene evidence to establish patterns. A baseline of comparison is used to establish if crimes are linked.
   Interpersonal coherence: how the offender interacts with the crime scene and the victim may reflect their everyday behaviour. E.g. is a rapist apologetic or do they want to humiliate the victim

Significance of time and place: can indicate where the offender lives/work

Forensic awareness: behaviour may suggest previous criminal experience/arrest
E.g. do they remove forensic evidence

Question 3

Outline geographical profiling.

Answer 3

• Information about the location of linked crime scenes which is called crime mapping.
  It is based on the principle of spatial consistency - people usually commit crimes in a limited geographical area (close to where they live or work)
• It provides ideas about where offender lives, works, what knowledge they have of a particular area etc to help target investigative efforts and prioritise suspects

Circle theory: the majority of the time, if a circle is drawn that encompasses all of a series of linked crimes, the offender will be based somewhere within the circle.
Commuter
Commit their crimes away from where they usually live
Usually organised

Marauder
Commit their crimes close to where they live or feel secure.
Usually, disorganised

Question 4

Evaluate

Answer 4

+Research support – investigative psychology: Canter and Heritage analysed 66 sexual assault cases using smallest space analysis and found case linkages due to specific consistent behaviours displayed.

• Case linkages rely on database information: which includes historical cases which may have been solved due to straightforward links being found between the cases.

+ Research support – geographical profiling: Canter and Lundrigan analysed 120 US serial killer cases using smallest space analysis and found spatial consistency in the behaviour of the killers and where the bodies were dumped, especially marauders.

• Insufficient geographical information: geographical profiling should not be used in isolation as data suggests 75% of crimes are never reported.