Normative standards
Limitations of tentative ID
Nuclear DNA
Biological profile: Asian
Biological profile: ancestry
Biological profile: age (and stature) of adults
Sources of DNA: Live person
Sources of DNA: Dead person
To properly compare fingerprints...
Biological profile: African
Biological profile: age (and stature)
Biological profile: male
Biological profile: age (and stature) of juveniles
Biological profile: (age and) stature
Tentative ID
Two types of DNA
Plastic print
Biological profile: European
Three patterns of fingerprints
Mitochondrial DNA
Limitations of normative standards
Identification
Positive ID
Limitations of using bone ossification to age juveniles
Visible print
Automated Fingerprint Identification System (AFIS)
Latent fingerprint
DNA Comparison
Identification methods
Bertillonage
Biological profile: sex
Biological profile: Female
DNA Databank
Three fundamental principles/characteristics of fingerprints
Steps in identification
Nuclear DNA: any nucleated cell; blood (white blood cells), buccal smear (epithelial/skin tissue), hair follicle (root) mtDNA: doesn't have to come from nucleus; hair shaft
Biological profile (forensic anthropology), surgical implants, facial approximation, video superimposition, materials at the scene, circumstantial, tattoos, visual ID (Positive methods: DNA, fingerprints, dental records, medical implants, frontal sinuses)
First question asked in death investigation. To determine the killer, identity of victim must be known. Often, when victim is not identified, the crime is not solved.
It might be this person; provides a potential name to a victim. Based on description, biological profile, items associated with body, case history, ID documents.
Nuclear DNA and Mitochondrial DNA
A fingerprint made when the finger deposits a visible material such as ink, dirt, or blood onto a surface.
Cranium - smaller Forehead - high in height, vaulted Brow - Smaller Mastoid process - diminished Pelvic opening - wide, circular Sacrum - short, wide, flat Subpubic angle - wide (right angle) Femur - narrow, angled inward
Age can only be presented as a range. In juveniles, the range is narrow and more precise - based on growth. In adults, range can be very wide - based on degeneration which is highly variable.
1. Is the victim human? 2. Describe the victim biologically 3. Tentative ID 4. Positive ID
A statistical term to describe the baseline of what is normal or average within a given population
A fingerprint made by the deposit of oils and/or perspiration, invisible to the naked eye. Can be visualized using fingerprint powders; iodine fuming; ninhydrin; physical developer; and superglue fuming. Alternate light sources induce fluorescence of fingerprints.
Must be compared to antemortem record to be of any use. DNA gives profile, not ID. Compare DNA from A (unknown body) with sample B from premortem record of tentative ID person.
Unique, shuffling from both parents. Could get premortem sample from parents/siblings. Problem - if two same-sex siblings are missing then we can only determine that victim is the child of the parent, but not which one. Need child's DNA - if one missing had a child, it could be determined.
Eye orbits - square/rectangular Nasal cavity - wide Incisors - smooth Jaw - prognathic (outward) Nasal bridge - flat
Compare unknown to known (UK) and must have premortem record
Family line, maternal inheritance
Cranium - larger Forehead - low, sloped, rounded Brow - pronounced Mastoid process - pronounced Pelvic opening - narrow, not circular Sacrum - longer, thinner, pointed inward Subpubic angle - narrow (acute) Femur - thick, straight
Eye orbits - oval Nasal cavity - long, narrow Incisors - smooth Jaw - flat Nasal bridge: angled
A fingerprint impressed in a soft surface
It is this person; provides a definitive name to a victim. Tentative ID determined first so that options are narrowed down. Determined through DNA, fingerprints, dental/medical records. Cannot be anyone else.
Cranium, forehead, brow (supraorbital ridge), mastoid process, pelvic opening, sacrum, subpubic angle, femur. Female pelvic features more exaggerated/wider. Male cranium features more robust. Cannot be determined in juveniles who have not yet gone through puberty.
Converts images of fingerprints into digital minutiae to make 1000s of comparisons per second - makes no final decisions about identity
May be more than one person who fits description; items with body may not belong to body, so ID must be confirmed.
Eye orbits, nasal cavity, incisors, jaw, and nasal bridge. Challenging to assess in mixed populations. Determinations for sex, stature, and age usually require known ancestry to improve accuracy.
Early method of anthropomorphic identification created by Alphonse Bertillon (1879). A system of identification using 14 physical characteristics scored with five rankings. The system was premised on the false idea that all characteristics are inherited independently, causing the major flaw that for the probability of two people having all the same ranks for characteristics is too rare, but because many characteristics are inherited together the probability of two people sharing some features is quite high. It was replaced by fingerprinting, which is now used alongside DNA and dental records.
Stature regression equations based on long bone length
Loop, whorl, and arch
Fresh body - blood, tissue, hair root. If decomposed or skeletonized - bone marrow, teeth (dentine, under protective enamel) mtDNA: hair shafts
Eye orbits - circular Nasal cavity - small, rounded Incisors - shovel-shaped Jaw - either flat or prognathic (outward) Nasal bridge - either angled or flat
Differences due to sex, population, and nutritional levels. Duration of ossification varies in published databases - some publish start of ossification, others how long it takes to complete; some break ossification into several stages; reference sample may not match remains
Bone wear and degenerative changes (such as arthritis), changes to pubic symphysis and auricular surface, smoothing and obscuring of cranial sutures
Centres of bone ossification/epiphyseal fusion, dental eruption, length of long bones (infants only)
(1) A fingerprint is an individual characteristic. No two are alike. (individual) (2) A fingerprint remains unchanged throughout life. (unchanged) (3) Fingerprints have general ridge patterns that allow them to be classified into three categories: loops, whorls, and arches. (classifiable)
Offenders convicted of serious crimes, such as sexual assault or homicide. DNA taken in investigation is not entered in databank. Additional warrant required post-conviction - samples taken during investigation destroyed. DNA comparison can be from databank or family member or personal item.
Assumption that humans are proportional; challenging to asses in mixed populations; may not include all of human variation; standards may not exist for every population; similar populations may not be transferable (black Americans =/= black Africans)
