Flashcards in Environmental Deck (28)
What are environmental specialist areas?
Palynology-pollen and spores
Macro plant ID- whole plants & ‘bits’
Vomitology- food remain from stomach contents or vomit
Sedimentology- soils and sediment
Entomology- flies and other insects
Techniques apply individually or collectively
Not always valid
What can plants and soil as evidence show?
Evidence of contact
Evidence of duration
Trace evidence off scene or at scene
Corroborate other scientific techniques
Find buried remains, target search areas and rule out others
What is evidence of contact?
Suspect/object with places
What is evidence of duration?
Events, sequences, timings
What are potential sources of sediment transfer?
Footprints and scuff marks
Plants damaged by suspect
Plant fragments/ pollen/ soil taken off site by suspect on clothing, tools & vehicles
Food/vomit (match to stomach contents) on site
What is involved in site sampling?
Pollen/ soil samples are always taken if outside
Sampling done before site trampled/strimned
How long does soft vegetation hold shape of something like a footprint?
What kind of local and regional input does pollen theory have on the profile?
What is the benefit of pollen theory?
Links suspect to locus type
Best corroborated by soil
What sort of landscapes can pollen theory indicate?
What do wind pollinated plants show?
Released large amount of pollen
Includes many trees
Pollen widely dispersed
Indicates vegetation of wider area
Not good for targeting specific sites
Smooth aerodynamic grains- tens of thousands (chance)
What do insect pollinated plants show?
Produce small amounts of pollen
Brightly coloured flowers
Includes many weeds
Fairly site specific, as pollen does not travel far
Pollen often sculptured to adhere to vector
Easier to identify bodies- smaller regions
What do self-pollinated plants show?
Release trace amounts of pollen
Immediate/proximity required to collect pollen of these types
Cereals are self-pollinated
What other factors are important in pollen theory?
Plants in flower are important
Rare plants/ vegetation important
Top 2mm has most recent pollen
What is the value of pollen evidence?
Target search areas
Site profile compared to victim, suspect, objects
What are the issues with pollen evidence?
High contamination potential- search personnel, floral tributes
Validity drops quickly as time since crime lengthens (uncompromised)
Often ID only to type not species- different habitat requirements
What is soil analysis theory (Geoforensics)?
Soil transfer links people/ objects to locus
Clothing, weapons, tools, footprints, vehicles etc.
Soil from putative ‘grave’ can ID if corpse ever present
Corroborates other evidence, especially pollen
Like pollen, requires care to avoid contamination
What makes soil identifiable?
Mineralogy of the area
Stone content (round, sharp etc.)
Organic content (how much, what does it comprise of?)
Inclusions (e.g. coal spores, diatoms)
Stratigraphy (layers of soil)
What analytical techniques are used in pollen theory?
Colour: good initial, Comparative tool
Particle size: laser-determined accuracy
Geo-chemical: phosphate, organic content (tell if body has been in empty grave)
Mineralogy: type/ shape/ size of minerals
Magnetic susceptibility: ID if soil burnt
Who collects soil and pollen samples?
SOCO (Scene Of Crime Officers)
What are control samples used for?
Vital for comparison
What is required when storing pollen and soil samples?
Long term stable storage
What is Macroplant remains (Forensic Botany)?
Plants have preferred habitats and life-stages
Helps ID suspicious changes to plants/vegetation
Vegetation damaged/covered/growing through graves give info on events and timings
Plants and fragments can ID seasonality and minimum deposition time
What is Vomitology (Food in stomach/vomit)?
Recovered from the scene or PM
Majority of foods plant based
Stomach acid means contents unchanged until torso decays (weeks or months)
Last meal(s) can be determined
Digestive erosion and volume of food helps ID time since consumption
ID vomit can exclude victim and target a suspect
How is stomach contents used as evidence?
Trace last movements (fast food agents, urban CTTV, till receipts etc)
Reduce window of death (days, weeks, hours)
Link victim to perpetrator
Yield lifestyle info about victim or perpetrator
What do Forensic Entomologist (flies/insects) do?
Flies, insects and beetles colonise corpse at various, known times after death
Blow flies arrive within minutes- unless in fridge, freezer, bin, after 4 days can’t follow vapour trail
Times to complete life cycle depends on temperature
Life stages of each species are identifiable
Helps ID duration of remains
Where do insects lay eggs in remains?
In any holes in skin e.g. shot wound, anus, stab wound