Forensics Flashcards
(109 cards)
offender profiling
a behavioural and analytical tool intended to help investigators accurately predict + profile characteristics of unknown criminals. narrow field of enquired + likely suspects. from intense scrutiny of crime scene + evidence
top down approach
From US, carried out by FBI in 1970s. FBI - data gathered from in depth interview w 36 sexually motivated serial killers (ted bundy). match what they know bout crime + offender and compare/match to pre existing template that FBI developed. criminals (specifically rapists/criminals) can be classified as organised or disorganised from evidence
constructing FBI profile
- Data assimilation (reviewing evidence)
- Crime scene classification (organised/disorganised)
- Crime reconstruction (hypotheses of sequence of events ect.)
- Profile generation (hypotheses about offender)
organised criminal features
- planned + controlled so little evidence left (may operate w almost detached surgical predictions and victim deliberately targeted)
- employed (skilled)
- average/high intelligence
- socially + sexually competent
- leads orderly life + commits crime after an event ( may be married w kids)
disorganised criminal features
- commits crime in act of passion (spontaneous - victim dead usually = no control)
- no evidence of pre planning
- below average intelligence
- poor work history
- socially incompetent
- dysfunctional/failed relationships
- lives close to where offence took place + live alone
Top down approach evaluation - limited application
P - Top down profiling applies to particular crimes
E - best suited to crime scenes reveal important details bout suspect like rape, arson + cult killings
E - method of profiling doesn’t help when crimes more common like burgarly, crime scenes reveal little info bout offender
I - reduces ability for profiling method to be used to identify criminals
Top down approach evaluation -
P - too simplistic
E - behaviours describe organised + disorganised types of offenders aren’t mutually exclusive. eg crime scene can have combination of organised + disorganised characteristics
E - suggest top down profiling may be not be valid way to categorise offenders
I - led to other researchers to propose more detailed typological models like holmes’s who said that there were 4 types of criminals
Top down approach evaluation - behav not same
P - based i ideas that people’s behav to be main same across situations + contexts
E - eg personality drives behav + isn’t impacted by external factors. Several critics have argued this is incorrect + behav is driven by aspects other than personality which r changeable
E - eg some criminals may be affected by certain situations than others + therefore some criminals may commit crime where others wouldn’t
I - reduces validity of top down profiling as it might not be possible to predict offenders next move
bottom up approach
largely developed in uk + more scientific and empirical. generate a pic of the offender (characteristic, routine behav + social background). thro systematic analysis of evidence at crime scene
difference between top and bottom approach
bottom approach :
- doesn’t begin w fixed typologies
- profiles r data driven
- profiles emerge as investigation looks at details
investigate psychology
matches details from crime scene w statistical analysis of typical offender behav patterns based on psychological theory. applies statistical procedures w psychological theory to analysis of crime scene evidence to develop a statically database which can acts as a baseline for comparison. specific details of offences can then be matched against database to relate info bout offender
investigate psychology - eg
railway rapist
- duffy assaulted 24 women + killed 3
- Canger interest in geographic deaths + evidence and combines this w similar attacks
investigate psychology - 5 features
- forensic awareness
- time and place
- criminal career
- interpersonal coherence
- criminal characteristics
forensic awareness
describes indiv who have been subject of police interrogation. useful for understanding lifestyle of criminal
time and place
behav shown in committing crime is behav they would show in their normal lives. can also show where they may be living
criminal career
if they leave little physical evidence then they may ages committed a crime before
interpersonal coherence
how offender behaves toward victim. there’s a consistency between way offenders interact w victims + others in their everyday lives - this helps police by putting offenders into a category
criminal characteristics
characteristics bout offender can help to classify them, which helps police investigation - looks at how experienced they r + what they might do next
geographical profiling
based on principle of spatial consistency. offenders operational base + possible future offences r revealed by geographical location of their previous crimes. uses george pics info to find crime pattern. can make inferences bout likely home or operational base + can tell bout perpetrators familiarity w area (models of offender behav). serial offenders will restrict crimes to geographical areas they r familiar w.
‘centre of gravity’ - offenders base.
‘jeopardy surface’ - where they may strike next
canter’s circle theory
commuter - criminals won’t likely to have travelled away from their usually residence
marauder - criminals who operate in close proximity to their home base
circle will likely form around their usual residence + this becomes more apparent the
more offences there r. can give insight into nature of offence ( planned/ opportunistic) + info bout offender
bottom up approach evaluation - support
P - evidence to support use of statistical analysis in investigative psychology.
E - Canter and Heritage (1990) conducted content analysis of 66 sexual assault cases. A computer program used to identify correlations across patterns of behav. E - Several common characteristics were identified. supports usefulness of investigative psychology as statistical techniques can be applied.
I - can lead to understanding of how an offender’s behav may change or whether 2 + offences were made by same offender.
bottom up approach evaluation - support for geographical profiling
P - evidence to support use of geographical profiling in identifying offenders.
E - Lundrigan and Canter (2001) collected information from 120 murder cases involving serial killers in the US. The location of each body disposal site was in a different direction from previous sites creating a ‘centre of gravity.
E - supports Canter’s claim spatial information is key factor in determining the base of offender.
I - because offenders base was also found in centre pattern meaning offenders could be tracked due to geographical profile made.
bottom up approach evaluation - failures
P - had some failures + studies examining effectiveness of top-down approach has got mixed results.
E - Copson (1995) surveyed 48 police forces and found that the advice provided by the profiler was judged to be ‘useful in 83% of cases.
E - shows although it can be effective, some profiles can cause police to incorrectly identify offenders.
I - impact of this is that some offenders may never be apprehended or innocent people resembling police profiles may be arrested instead.
atavistic approach
biological approach to offending that s criminal activity r genetic throwbacks ill-suited to conformity to society’s standards.