Identification
likelihood ratio
- > 1 = more likely correct match - < 1 = less likely correct
common x-rays
-40% chest -10% limbs -7-8% spine/breast -5% abdomen/head/neck/pelvis
ident from surgical interventions
-product or brand ident # on the implant -could give (+) ID or just narrow down the pool -identification of ident # may be obscured by remodelling bone -placement is not consistent b/w implants
hard tissue comparisons (5)
-radiographs -surgical interventions -DNA -facial superposition -facial approximation
what does a patgologist use for identification?
-soft tissue -eg fingerprints, scars, birthmarks, tattoos
positive ID
-successfully demonstrates individualization -expert confirmation of unique characteristics -eg dental records, x-ray, etc
types of identification (3)
-tentative -presumptive -positive
how do we narrow down or options?
-biological profile -individualizing features -PMI
using DNA for ident
-body fluids, skin, hair, bone, teeth -considered a unique feature -can determine sex: eg enamel gene -can identify perp, victim, or rule out suspects
using radiographs for ident
-compare AM vs PM -odontology, frontal sinuses, previous trauma, pathological conditions
3 determinations we can make based on identity comparisons
-consistent -not consistent -insuffiecient information
forensic odontology
-dentition is unique (160 unique surfaces) -restorations, dental work, tooth orientation, wear -enough to narrow down the pool at least, not necessarily enough for a (+) ID -combination of all dental traits = 99% confident
using tattoos for ident
-fairly common ident -requires soft tissue and fairly recent remains -not (+) ID, tentative
3D facial approximation
-fill in missing elements of skull, add eyes -place tissue depth markers (based on age, sex, ancestry) -connect markers w/ clay based on markers -add soft tissue features (using artistic license here)
what does a FA use for identification?
-hard tissue -eg DNA, medical records, surgical implants, dental records
craniofacial superposition
-image or 3D rendering of decedent's skull is superimposed over a photo of a missing person -presumptive ID -images must be in the same angle and plane
presumptive ID
-inclusion of additional ID attributes -eg place of death
personal identification
-linking unknown objects/remains back to an individual -informed by context, personal attributes/features/belongings, investigative information, scientific tests/comparisons
tentative ID
-suspected ID based on circumstantial materials -eg driver's license, things friends/family say about why it's them, etc
2D facial approximation
-tissue depth markers -photograph skull -contours drawn onto transparent vellum sheet -skeatch in features
using fingerprints for ident
-unique feature present in recent deaths and well-preserved bodies -can use degloving -ident officer compares prints to database -used as (+) ID but is debated
facial approximation
-used when we have no idea who the person is -becomes a stimulus for recollection -2D or 3D
probability statements
eg "99% chance/match to the individual"
population statistics
used to determine hoe may ppl have a certain feature to determine uniqueness