Forensics Flashcards
What is offender profiling
This is a behavioural and analytical tool used by investigators to accurately predict and profile characteristics of unknown offenders
What are the two approaches
Top Down - US
Bottoms up - UK
What is the top down approach and how does it work?
- In Depth interviews with 36 sexually motivated murders
- Start with pre established typology
- Data was categorised into organised and disorganised murders by using the witsness accounts and evidence
- By placing one characteristic into one category we can predict the other likely characteristics
What is the difference between organised and disorganised?
Organised offenders show evidence of planning targeting a specific victim.
They have high levels of control leaving little evidence, tend to have iq, stable relationships and careers
Disorganised offenders tend to have spontaneous, impulsive acts
They have evidence left, low iq, unskilled, unemployed,
How do you construct an FBI profile? - top down
- Data Assimiliation - Review evidence
- Crime scene classification - organised and disorganised
- Crime Scene reconstruction - sequence of events, behaviour of victim
- Profile generation - Hypotheses related to likely offender eg demographic, physical characteristics, behaviour
A03 - offender profiling - TOP DOWN
STRENGTH - Canter conducted an analysis of 100 US murders commited by a different serial killer each time
- A technique called Smallest Space Analysis used to identify correlations across different samples of behaviour
- He looked at 39 killings and whether there was torture, concealing of body, murder weapon and cause of death
- These features matched typology of organised characteristics
COUNTERPOINT
- there are a variety of combinations that occur at any crime scene so oranised typology more of a continuum
- STRENGTH - wide range of application for Top Down
> Meketa recently revealed it can also apply to burglary (85% rise in solved cases in US)
> Adds 2 new categories - interpersonal (steals something of significance) and opportunistic (inexperienced)
LIMITATION - Evidence on which it was based
- FBI profiling using 36 murderers in the US (25 Serial, 11 single/double murders)
- At the end 24 organised and 12 disorganised
- Not big sample
- No standard set of questions
What is the Bottoms up approach
Profilers work up from the evidence collected from the crime scene to develop hypothesis about likley characteristics, motivations and social background of the offender
What is investigative psychology
This is where they attempt to apply statistical procedures alongside psychological theory to the analysis of crime scene evidence in order to establish patterns of behaviour. This allows them to develop a statiscal database that allows for comparison
How does investigative psychology work - bottoms up
Specific details of an offence are matched against a database to reveal important details of an offender, personal history and family background
Central to the approach is the concept of interpersonal coherence where the way a criminal acts at the scene reflects their every day life
What is geographical profiling?- bottoms. up
This is where they use information about the location of linked crime scenes to make inferences about the likely base of an offender
What is the centre of gravity ?- bottoms up
The assumption that serial offenders will restrict their work to geographical areas they are familiar with meaning it can highlight the offenders base
What is Canters Circle Theory- bottoms up
- The pattern of offending forms a circle around the offenders home base
- The Marauder : operates in close promximity to home base
- The commuter : travelled a distance from usual residence
a03 offender profiling : bottoms up approach
STRENGTH : Evidence for investigative psychology
- Canter and Heritage used the smallest space analysis to analyse 66 sexual assault cases
- Several behaviours identified in different samples of behaviour such as impersonal language and lack of reaction to the victim
- This can help establish whether 2 or more offences were committed by same person
- Supports one of the basic principles of investigative psychology that people are consistent in their behaviour
STRENGTH : evidence to support geographical profiling
- lundrigan and canter collated information from 120 murder cases involving serial killers in the US
- Smallest space analysis revealed spatial consistency in the behaviour of killers and the location of each body disposal created a centre of gravity
LIMITATION : geographical profiling may not be sufficient on its own
- the success is only reliant on the quality of data that the police can provide
- Recording of crime is not accurate and 75% are not even reported to the police
- Other factors are just as important in creating a profile such as timing of offence, age and experience
What is the main point of the historical approach (biological explanations)
Lombroso suggests that criminals were genetic throwbacks - a primitive species who were biologically different from non criminals
What is lombrosos theory of the atavistic form?
Physiological markers that make offenders physically different to us
What are the features for the atavistic form?
The cranial characteristics
- Narrow, sloping brow
- Prominent Jaw
- High cheekbones
- Facial Symettry
Physical Characteristics
- dark skin
- extra toes, nipples, fingers
Other Aspects
- insensitivity to pain
- slang
- tattoos
- unemployment
What difference in categories did murderes and sexual deviants have
Murderers
- bloodshot eyes
- curly hair
- long ears
Sexual Deviants
- glinting eyes
- swollen fleshy lios
- projecting ears
- lips of fraudsters thin and reedy
What are the research/ statistics of Lombrosos research - historical approach (biological explanation)
- He examined the facial and cranial features of Italian convicts that were atavistic
- He concluded these were features of criminality
- Lombroso examined the skulls of 383 dead convicts and 3839 living ones and conluded 40% are commited by people with atavistic characteristics
a03 - biological explanations (historical explanations)
STRENGTH : Lombrosos study changed the face of the study of crime
- He coined the term criminology
- Shifted crime from moralistic to scientific
COUNTERPOINT
- racist undertones
LIMITATION : Contradictory evidence between atavism and crime
- Goring conducted a study comparing 3000 offenders with 3000 non offenders
- No evidence that offenders have unusual facial and cranial features
LIMITATION : Poor control
- He did not compare offender to non offender group
- Counfoundig variables that could have been present for higher crime rates
- Research has demonstrated links between poverty and poor education to unemployment
- lombroso doesnt meet modern standards
3 factors that support genetic explanations (biological)
Twin and adoption studies
Candidate Genes
Diathesis Stress
How do twin and adoption studies support genetic explanations?
- 3500 twin pairs studied in Denmark
- Concordance rates of 35% for MZ and 13% not DZ
- Not just behavior inherited but underlying predisposing traits
- Crowe found that adopted children whose biological mother had a criminal record had a 50% chance of having a criminal record by age of 18 and those that didnt have criminal record of only 5%
How do candidate genes support genetic explanations?
- Analysis of 800 finish offenders that suggested two genes MAOA and CDH13 associated with violence
- MAOA regulates serotonin and liked to aggression
- CDH13 links to substance abuse and ADHD
What percent of severe violent crime in finland contributes to the genes
5-10% of severe violent crime attributes to maoa and cdh13
How do diathesis stress support genetic explanations?
Combination of genetic predisposition and biological/psychological trigger