Topic 3 Biochemical Analytical Technique Part-1 Flashcards
Describeforensicentomologyincriminalinvestigations. what are 2 the things we study about the insects? what are the 3 things we can determine by studying the insects?
Forensicentomologydenotesthestudyandapplicationofinsects/arthropodsasevidenceinalegalinvestigation.
Bystudyingthe1. insectpopulationandthe2. developinglarvalstages,
forensicscientistscanestimatethe1. postmortemindex,2. anychangeinpositionofthecorpseaswellasthe3.causeofdeath.
2.What is forensic anthropology? Describethe 3 methodstodetermineskeletalageofremainsbytheforensicanthropologist. stae the age of the specimens that each technique can be used for
ForensicAnthropologyisthestudyofhumanskeletalremainsthatinvolvesapplyingskeletalanalysisandtechniquesinarchaeologytosolvingcriminalcases.
Threetypesofmethods:
1)FUN(Fluorine,Uranium&Nitrogen)dating<100 years
Usefulonlyforcomparingsamplesfromthesame sitebecauseFandUingroundwater/mineralsvaryfromonesitetotheother. Note that nitrogen decreases while F and U increase
2) FluorescenceSpectroscopy: Indicates100-400 years old
3) carbon 14 dating: Forveryoldhumanremains(>400-50 000 years old)
3.DefineBloodstainpatternanalysis(BPA)anddescribeitsroleincriminalinvestigations. what do analysts stud about the blood stains?
what are the 3 types of blood patterns?
Bloodstainpatternanalysis(BPA)istheinterpretationofbloodstainsatacrimescene
inordertorecreatetheactionsthatcausedthebloodshed.
ThegeneralroleoftheBPAinacriminalinvestigationisto:
assistinthereconstructionofthoseeventsofanallegedincidentthatcouldhavecreatedthestainsandstainpatternspresentatacrimescene,onitemsofphysicalevidencerecoveredfromthatsceneandonitemsofclothingthatwerepresentatthecrimescene.
Analystsexaminethesize,shape,distributionandlocationofthebloodstainstoformopinionsaboutwhatdidordidnothappen.
TypesofPatterns: (i)Passive(ii)Projected(iii)Transferorcontact
what are some units/ labs that can be found in a forensics lab?
- DNA lab
- Firearms unit
- Documents unit
- Photography unit
- Toxicology
- latent fingerprints
- poly graph
- voice print
- psychiatric profiling
- computer and electronic forensics
- forensic entomology
- forensic geology
- facial reconstruction
- forensic anthropology
- forensic odontology
what is another term for time of death?
post mortem index/interval
what is a latent fingerprint?
afingerprintleft on a surface by deposits of oils and/or perspiration from the finger.
It is usually not visible to the naked eye
what are the 3 principals of laten fingerprinting?
First Principle –No two fingers have the same prints including identical twins (twins might still share same DNA!)
Second Principle – fingerprints do not change during a lifetime (and remain after death for some time)
However, they might fade away due to aging, scarring or genetic
Third Principle
– patterns can be classified
(ridge ending, bifurcation, lake, independent ridge, dot/island, spur and crossover)
what are the 3 qualitative analysis techniques used in latent fingerprint visualisation? DVL
1)DustingPowder(accordingtobackground contrast)
-MolybdenumDisuphide
-Aluminium
-carbonblack
liftprintontape
2)Visualisation Reagents
-Ninhydrin(applyandheat)
reactswithamino acids
–IodineSpray
–SilverNitrate
3)Laserfluorescence Spectroscopy
aloneorusinga dye
what is the qualitative AND quantitative analysis technique used in latent fingerprint visualisation? What is its advantage?
Fourier transform infrared (FTIR) microscopes:
FTIR coupled with a high resolution microscope
non-destructive qualitative & quantitative technique
Analytical tool to visually and chemically analyse illicit tablets, hair, fibers, inks, and paints found in a crime scene.
what are fingerprint databases?
Electronic databases
- Fingerprint database - criminals
give close matches but not perfect matches.
Human judgement is still required.
