Test 5 - Fingerprints, Death and the Body, Autopsy and Unnatural Death, Forensic Odontology

Flawed Bertillon System

• Anthropometry

• Will and William West case

  • Although the two men were similar enough to be identical twins, they were not related

    • Prints were different

Skin Ridge Purpose

• Provide firm grasp

• Resist slippage of feet

Ridge Types

• 150 individual ridge characteristics

• Three basic print patterns

  • Loop - whoop'; most common

  • Arch - hill over hill over hill; rarest

  • Whorl - eye of the storm; medium commonality

Minutiae Points

• Most courts require 14 to 16 matched minutiae for a positive match

• Examples

  • Dot/island - dotted line

  • Bifurcation - two-pronged fork

  • Trifurcation - three-pronged fork

  • Enclosure - circle interrupting a line

  • Bridge - cross from one ridge to another

  • Spur - dead-end street coming off of the ridge

Subclassifications

• Arches

  • Plain Arch

  • Tented Arch - higher slope

• Loops

  • Radial Loop - left entry

  • Ulnar Loop - right entry

  • Double Loop - two interlocking loops

• Whorl

  • Plain Whorl

  • Central pocket whorl - loops around the circle

  • Accidental Whorl - whorl with a loop wrapped around it

Henry System of Classification

• based on whorls

R. Index R. Ring L. Thumb L. Middle L. Little

R. Thumb R. Middle R. Little L. Index L. Ring

1. Set up these fractions

2. Whirls 1st column fingers = 16

2nd column fingers = 8

3rd column fingers = 4

4th column fingers = 2

5th column fingers = 1

3. Tally numbers

Can you change Fingerprints?

• Not all patterns on hand

• Needs wound down 2mm into skin

• Fingerprints are formed underneath the skin in the dermal papilae. As long as that layer of papilae is there, fingerprints will always come back, even after scarring or burning

• Scarring can make you more individualistic

• John Dillinger

Automated Fingerprint Identification System

• Database for storing prints

• Automatic scanning devices convert FP image to digital minutiae showing ridge endings and bifurcation

• Stores and retrieves FP record

• Thousands of comparisons in seconds

• Produces list of file prints w/ closest correlation

• National Institute of Standards and Technology exchange of data between AFIS systems

• Final verification by FP expert

Visible Prints

Two-dimensional

• Blood

• Paint

• Grease

• Ink

Plastic Prints

Three-dimensional

• Impressions in putty, wax, soap dust

Latent Prints

an invisible print made of perspiration, oils, and amino acids

Fingerprint Powders

• If hard, nonabsorbent surface (glass, tile, etc)

• Soft brush

• Powder sticks to perspiration

Iodine Crystal Fuming

• If soft, absorbent surface (paper, cloth, etc.)

• Crystal undergoes sublimation (solid to gas)

• impermanent development

• Gold-brown

Ninhydrin Spray

• If soft, absorbent surface (paper, cloth, etc.)

• Reacts with amino acids in perspiration to produce purple development

RUVIS

• See latent fingerprints before development

Algor Mortis

• The change in body temperature

• Temperature falls at about 1.5^oC/hour

Science:

• No more heat-generating chemical reactions

• No more homeostasis by brain of body temp

• Diffusion of heat until at equilibrium with room temperature

• Faster in windy conditions and in water

• Children and thin people cool faster

Livor Mortis

• Settling of red blood cells

  • this reddens the skin

• Begins within 30 mins

• Most evident within 12 hours

  • After that, liver mortis will not move regardless of how the body is moved

Science:

• Heart stops

• Vessels break down

• Red blood cells are dense and settle according to gravity in body

• Pressure moves blood cells

• Can see if body has been moved after death

Rigor Mortis

• Board-like stiffening in about 12 hours, lasts another 12 hours, and releases in another 12 hours

Science:

• No blood pumped

• No oxygen to muscles

• Bacteria doing anaerobic respiration

• Make lactic acid

• Low pH causes Actin and Myosin to contract muscles, so they stiffen until ATP is gone and fibers decompose

• Stiffening begins at the jaw and migrates down

Sung T’zu (1235)

first reference to forensic entomology

Stages of Decomposition

1. Fresh Stage (days 1-2)

• Commences at death, ends when bloating is first evident

• Breakdown of protein and carbs into simpler compounds

2. Bloated Stage (2-6)

• Putrefication begins

• Gases produced by anaerobic bacteria inflate the abdomen

3. Decay Stage (5-11)

• Abdominal wall breaks

• Gases escape - carcass deflates

4. Post-decay Stage (10-25)

• In dry habitats, remains are skin, cartilage, and bones

• In wet habitats, wet, viscous materials in the soil under the remains

5. Dry Stage (25+)

• Mainly bones and hair remain

• Odor is primarily that of normal soil and litter

• Can last several months or years

Blowflies

the first bug to get to a decaying body

Decay Stage

• Abdominal wall breaks

• Gases escape - carcass deflates

Dry Stage

• Skin and bones

• Insects with the ability to digest keratin (clothes moths, mites, and dermestid beetles)

Decomposition and Season

• Fastest in the summer

• slowest in the winter

Post-Mortem Interval (PMI)

time from a death to the discovery of a cadaver

Fly Development

1. Lay eggs

2. Egg stage

3. Maggot hatches

4. Stage 1 maggot

5. First molt

6. Stage 2 maggot

7. Second molt

8. Stage 3 maggot

9. Maggot becomes a pupae

10. Puparium

11. Fly emerges

Factors Related to Insect Decomposition

1. Geographical locality

2. Seasons

3. Competitors

4. Habitat

   1. Shaded vs. open, forest vs. field vs. roadside, wet vs. dry)

5. Urban vs rural

6. Enclosed space

   1. Car trunk, house, wrapped in blankets or plastic

7. Condition of body

   1. size/weight frozen, buried, burned, submerged, disarticulated, wounds, body moved after death

8. Buried vs Unburied

   1. unburied is faster

Coroner vs. ME

Coroner - elected official

Medical Examiner - medical degree

Chain of Custody in an Autopsy

recorded on the toetag

Evidence Preservation in an Autopsy

hands and feet covered with bags to prevent loss of potential evidence

Abrasion

• A “scrape”

• Occurs when the skin contacts an opposing surface and the movement of either the skin or the surface results in friction that pulls away the superficial layers of skin

Contusion

• A “bruise”

• Blood vessels tear, resulting in the escape of blood into the extravascular space

• Classes: petechiae, purpura, ecchymoses, and hematoma

Ligature Marks

• Patterned bruising made by an item of cord, rope, or some such material

• Made by strangulation or immobilization

Incision

• A clean cut on the skin that is made with a sharp object

• Knife or blade

Laceration

• Caused by the skin and tissue either being twisted, stretched or ripped to the point of splitting

Puncture

• a hole

• Caused by a sharp pointy object such as a nail, animal teeth, or a tack

• Does not usually bleed excessively and can appear to close up

Strangulation

• Ligature marks on the throat

• Popped blood vessels in eyes

• Bone in neck broken

Blunt Force Trauma

caused by hitting the body with a blunt object

Dissection

• dissect each organ and examine

  • weigh to gauge problems with the organ

• most unnatural deaths are due to alcohol poisoning/consumption

Paul Revere

• First forensic dentist in the US

• Identification of fallen revolutionary soldiers

Forensic Odontology

a subspecialty of dentistry that has as its main focus on the identification of deceased persons

White in X-rays

fillings or root canals

Teeth Impressions

take impressions to conclude guilt in a crime