forensics- offender profiling Flashcards
top down and bottom up approach
what is offender profiling? method of…
method of working out the characteristics of a offender by examining the characteristics of the crime and crime scene.
aims to narrow down the number of potential suspects.
analyse crime scene + other evidence (eg ewt)»_space; generate hypotheses about characteristics of offender eg age, background, occupation
what are the 2 approaches of offender profiling, and which country tends to use which
top down (USA) and bottom up (britain)
what is the difference between mass, spree and serial murder
mass- one incident with no significant time interval (many, simultaneously, close proximity)
spree- more than one murdered, killed over a short period of time (2+ locations)
serial- more than one murdered, killed over an extended period of time eg several months
top down approach to OP is also known as
crime scene analysis
what is the top down approach to OP, overall?
analysis of previous crimes creates a profile of a likely offender, creating categories (organised/disorganised) containing characteristics.
a profiler intuitively applies their prior knowledge on these categories/profiles to get a “feel” for the kind of person who committed the crime.
so data about murder is collected (characteristics of murderer (if known), crime scene etc) then decide what category
aims to produce a profile of the most likely offender
relies on intuition and beliefs of the profiler
has several stages
characteristics of an organised type of offender
crime is planned/highly controlled
victim specifically targeted (has a type)
body transported from scene
weapon hidden
little clues left
violent fantasies carried out on victim
highly intelligent
socially and sexually competent
follow their crimes in the media
live with a partner/married/kids
have a working car
characteristics of an disorganised type of offender
unplanned crime/spontaneous/lack of control
random selection of victim
engage very little with victim
low IQ
unemployed/unskilled work
history of sexual disfunction
failed relationships
live alone (potench close to crime add)
sexual acts are performed PM on body
crime scene has clues eg blood, semen, prints, body, weapon /reflects impulsive nature of crime
what are the six stages of the top down approach
profiling inputs
decision process models
crime assessment
criminal profile
crime assessment
apprehension
what is the profiling inputs stage of top down approach to OP
collect data inc description of crime scene (photo + sketch), background info on victim (employment, habits, relationships), deets of crime (weapon, COD/autopsy report)
all info should be included
possible suspects not considered (may bias info collected)
what is the decision process models stage of top down approach to OP
profiler organises data into patterns
may consider: murder type (mass/spree/serial), time factors (length of crime short/long, day/night), location factors (was crime scene (kidnap from) same as the murder scene))
what is the first crime assessment stage of top down approach to OP
based on data collected, crime is organised into organised or disorganised (presumes correspondence between offences and offenders)
what is the criminal profile stage of top down approach to OP
profile constructed inc Hs about likely background, habits, beliefs
description is used to work out strategy for investigation to catch offender
should anticipate how offender may respond to investigative efforts eg how should they be interviewed
what is the second crime assessment stage of top down approach to OP
a written report is given to investigating agency eg police and people matching profile are evaluated
if new evidence is generated +/ no suspect is identified go back to step 2 (DPMs)
what is the apprehension stage of top down approach to OP
if a suspect is apprehended the entire process is checked to make sure its legit/valid
and consider how process may be revised for future cases
strength of top down approach: support for usefulness > copson questioned…
copson questioned 184 us police officers and 82% said TDA was useful and 90+% said they would use it again
it could be said that the TDA is useful because it gives other contributions. eg a different perspective to the investigation and new avenues for investigation and it may prevent wrongful conviction
limitation of TDA: distinction between categories has been criticised, douglas said … and canter
said you need 3 categories inc a new mixed one for inc org/disorg characs, however this could lessen usefulness as it could act like a dustbin category
canter found evidence that it has little basis in reality. they analysed 39 aspects of serial killings by 100 us murderers. they found NO CLEAR division between org and disorg types of offender. and found a number of subsets of org crimes and little evidence for disorg.
so having 2 categories is too simplistic and it should be more of a continuum
limitation of TPA: the og data may be flawed, it came from eg ted bundy ….
the og data used to create org/disorg categories of op came from interviews with 36 of the worst murderers eg ted bundy and these characteristics are now used to help police “read” a crime scene.
these murderers arent a good source of reliable info and their approach and rational may be different to more “typical” offenders
so approach may not be reliable or generalisable to more common smaller scale crimes.
cp: the six stage process of the tda does allow more improvements to be constantly made
limitation of TD: isnt accurate as the data on usefulness can also be questioned in terms of how useful is it measured
how should usefulness be measured?
alison…
one way to measure usefulness is to consider how close the profile is to actual offender characs at the end of the case. if close demonstrates usefulness of methods
alison shows these judgements are not reliable. police officers were given a profile along with one of two versions of offenders actual characteristics (one being real). over 50% of officers rated the profile they were given as accurate even tho half were fake
what is the bottom up approach
it is a data driven approach where statistical techniques are used to produce predictions about the likely characteristics of an offender
aiming to generate a picture of the offender through systematic analysis of evidence at the cs, more rigorous scrutiny of details of the offence
how does BU differ from TD
BU is more scientific, doesnt begin with fixed typologies, BU is data driven with rigorous scrutiny of details of offence using systematic analysis, it is also grounded in psych theory
what are the 2 types of the bottom up approach
investigative psychology and geographical profiling
what is investigative psychology and what does it inc (bottom up)
it matches details of the cs with statistical analysis of typical offender behaviour patterns based on psychological theory
incs: interpersonal coherence
forensic awareness, significance of time and place, smallest space analysis
what is interpersonal coherence
if people are consistence in their B then there will be links/correlations with elements of the crime and everyday B.
the way an offender behaves at cs inc interaction with victim may reflect their B in everyday situations
also B changes overtime therefore looking at differences in crimes over time may give clues
what is forensic awareness
certain behaviours may reveal an awareness of particular police techniques and past experience eg davis found that rapists who conceal fingerprints often had a previous conviction for burglary
describes those individuals who have been the subject of police interrogation before, their B may denote how mindful they are of covering their tracks
