1. Notes on Forensics

2. Forensics What is forensic medicine? Latin word - forensics
Means public discussion or debate
Science used in justice system for legal purposes
Facts based on scientific investigation
Goal is to determine facts and truth
Uses multiple science specialties

3. Forensic Anthropology
Skeletal anatomy
206 bones
Man = 12 pounds
Woman = 10 pounds
What bones show
How person lived
Debilitation illnesses (rickets, polio, healed fractures)
Right handed or left handed
Clues to occupation

4. Forensic Anthropology
Questions about skeletal remains
Age of person at time of death
Sex of person (skull and pelvis)
Race
Height

5. Odontology 1. Characteristics of teeth after death
a. No other part lasts longer
b. In fires, teeth usually only means to ID remains
c. No two people have identical teeth
2. Requirements for identification
a. Need dental records
b. Dentists chart five surfaces of each tooth in a
grid (odontogram)
c. Can also provide “bite mark” evidence
3. Teeth useful in determining subject’s age

6. Autopsies Definition and Purpose To see for oneself
Surgical operation done on a dead body
To learn about person’s health and cause of death
Legal Requirements
Coroner
Medical examiner
Pathologist

7. Autopsies Reasons for autopsy
Determine which disease or injury caused death
Diagnosis - confirmation and understanding
Evaluate possible public health issue
Preparation
If not required by law, permission needed from next of kin
Legal consent form

8. Autopsies Procedure Complete medical history and review of records
External physical exam
Body tag
Weight and height
Clothing and valuables identified
Scars, tattoos, injuries, wounds, bruises recorded
Foreign objects noted
Photos and x-rays taken, if needed

9. Autopsies Complete internal exam Dissection of head and abdomen
Organs removed, weighed, measured, and examined
Tissue samples examined under microscope
Fluid samples tested for drugs, infection
After autopsy complete, legal death certificate
Results
Natural death – disease or old age
Unnatural death – unnatural, unexpected, or unusual cases

10. Autopsies Methods to determine time of death Traditional indicators
Rigor mortis
Begins three hours after death in face and
eyelid muscles
Takes twelve hours to affect entire body
Process reverses after 36 hours
Lividity (hypostasis)
Visible minutes after death
Red cells settle and skin below turns red
In 6-10 hours, color becomes permanent

11. Autopsies Body temperature Falls at rate of one degree per hour
Obesity and warm environment slows cooling
None of the above are totally reliable and can be manipulated

12. Serology Blood type Four types (A, B, O, and AB) Rh factor
Female cells have Barr Body

13. Serology
Criminology
Kastle-Meyer test to determine if it is indeed blood
Precipitin test – determines animal or human blood
Can determine type and gender from blood
Provides reliable and informative evidence

14. DNA What is DNA? Nucleus of cells contain RNA/DNA
DNA = deoxyribonucleic acid
Nucleus has 23 pairs of chromosomes made
up of DNA
Within each pair, one chromosome from
sperm and one from egg

15. DNA Typing What makes DNA individual?
Four chemicals: Adenine, Guanine, Cytosine, and Thymine
Chemical strung together=DNA code
Some sections of DNA vary from individual to individual
Scientists can link a strand of DNA to a given individual

16. DNA Typing Criminal investigations
Specimens: blood, hair, bloodstained clothing
Provides powerfully compelling evidence

17. DNA Typing

18. DNA Typing

19. DNA Typing

20. DNA Typing

21. DNA Typing
What are the chances that the DNA profile of a random person would match the crime scene DNA?
Multiply the individual probabilities:
0.01 x 0.05 x 0.1 x 0.02 =
Probe A 1%
Probe B 5%
Probe C 10%
Probe D 2%
1 person out of every 1 million could have left the DNA at the crime scene.

22. Other Tools Firearms and Toolmarks
Typically, this includes matching bullets to the gun that fired them.
Toolmark identification involves the identifying characteristics between tools, such as a pry bar, and the object on which it is used, such as a door frame.
Also included in the category are explosives and imprint evidence.

23. Other Tools Forensic Profiling
When a specially trained psychiatrist or investigator can examine certain crime scenes to come up with a personality profile of the offender.
Document Examination
This discipline involves all special relationships that may exist between document and inscription and how it relates to a person or sequence of events.
This includes forgery, counterfeiting, and handwriting analysis.