Geographic Profiling Flashcards
why geography
every crime location is the choice of the offender.
offender either travelled to the location or area to commit an offence.
offender may have been there for some other purpose when the decision to commit the crime was made
A CONNECTION/ KNOWLEDGE OF THE LOCATION IS LIKELY
theories and principles
four main theories relating to how crime location is chosen;
LEAST EFFORT PRINCIPLE
- zipf(1950)
- “when multiple destinations are of equal desirability, the closest one is chosen”
DISTANCE DECAY
-this describes the effect of distance on cultural or spatial interactions. The distance decay effect states that the interaction between two locales declines as the distance between them increases.
RATIONAL CHOICE THEORY
- the offender weighs up the costs Vs. the benefits before committing the offence to see if its really worth it.
ROUTINE ACTIVITY THEORY
- to choose a crime location, an offender must be aware of it. Offender identify suitable crime locations through the course of normal daily legit activities.
decision to commit the crime
SELECTED AREA
- has easy access
- few police patrols
- low security housing
- larger gardens
REJECTED AREA
- unfamiliar
- distant
- neighbourhood watch
- no public transport
different motivation - different choice
each offence will also impact on ow far the offender travels, how he identifies a relevant vehicle and how long he searches for
low value-joy rider
high value- illegal export
vehicle with high demand-resale of vehicle/parts
fast and reliable-get away vehicle
types of crime site
encounter site
attack/assault location
murder/rape scene
body deposition/release site
credit card usage
ALL OF THESE DIFFERENT SITES ARE INDICATIVE OF THE TYPE OF OFFENDER, whether they are organised, planned, spontaneous or opportunistic.
technology can only go so far
technology only predicts an anchor point based on the spatial relationship between crime locations.
They are ignorant to;
- underlying demographics/land use
- offender search methodology
- victim and offender movement
- type of crime/crime location
- temporal info
RIGEL
Validity, reliability and utility
optimal search strategy for appropriate integration into investigation
RIGEL is not always applicable
rigel is only one small element, all of these things will effect distance trvelled and location of offences/ how offender may be found
every case is different, you never know which part of your analysis will be relevant/conclusive/informative
producing a geographic profile
- identify what happened
- understand the criminal event
- ask questions
- apply theories
- formulate a hypothesis
- what Vs. why
- what stage is the investigation at
- apply to the investigation
- develop investigative strategies
investigative strategies
prioritisation of area;
- house to house
- leaflet drop
- DNA screen
- media releases
- body searches
- patrols
- decoys
-CCTV
main challenges
identifying the relevant data
being kept in the loop
changes in the investigation
inconclusive analytical patterns
persuading investigators of a course of action
Prioritisation Matrix
a matrix that sorts in order what it most important and least important to prioritise
temporal analysis
is the study of time
why do we analyse time ?
- to understand what has already happened
2. to predict what will happen in the future
what are the elements that are typically combined to identify a discrete temporal location?
date and time
A.M
ante meridian
P.M
post meridian
temporal distribution
how events are situated throughout the study area in relation to one another
what are the 3 classes of distribution ?
- CLUSTERED EVENTS- tend to occur in close proximity to one another
- UNIFORM EVENTS-tend to occur far apart from one another
- RANDOM EVENTS- are neither clustered nor uniform.
CASE EXAMPLE (sexual assault)
11 sexual assault cases in Bath city centre
all victims were socialising or returning from work when they were;
- approached in the street
- approached from behind
- hand up skirt
- disguise was worn
there is CCTV of the offender
offender DNA was obtained
producing a geographic profile
scene visit necessary
checking the detail
- what info do we have regarding the offences?
- is there any further info that could be obtained?
- how have the offences been linked?
- what searches have been carried out?
- has the offender carried out any other offences?
working through the data to identify patterns
YOU HAVE TO BE AWARE OF STATISTICS —-
cause/correlation (do they have a link?)
what is likely to happen by chance?
conformation bias
Toulmins logic (Stephen Toulmin, an English philosopher and logician, identified elements of a persuasive argument. These give useful categories by which an argument may be analysed)
putting everything together
what does the information suggest ?
should alternative hypotheses be considered?
what investigative strategies are suited to the enquiry?
how can i best report this to the investigation?
“no body” murder
professionals should research;
- knowledge of previous and similar cases
- timeline of the victims activity
- timeline of the offenders activity
- offenders personality and criminality
- offenders geography (current and past locations and travel)
