Forensic Science
the applications to matters of science to law
-As well as. . .
The business of providing timely, accurate, and thorough information to all levels of decisions makers in our criminal justice system.
Criminalistics
the scientific examination of physical evidence for legal purposes This term is synomous with forensic science
Criminology
includes the physcological angle, studying the crime scene for motive, traits, and behavior that will help to interpret the evidence
Divisions of Crime Lab
**Physical Science Unit
-chemistry
-physics
**Geology
**Biology Unit(DNA)
**Firearms Unit(tool mark)
**Document Examination Unit
**Photography Unit
Edmond Locard
**French professor
**Considered the father of: criminalistics( understood the importance of nature in crime scenes and other cases.)
**Built the world's first forensic laboratory in France in 1910
Exchange Principle
Whenever two objects come into contact with each other, traces of each are exchanged.
Alphonse Bertillon
Father of: criminal identification
Francis Galton
First to develop a method of: first to develop a method using fringerprints as a means of identification.4f
Dr. Karl Landsteiner
An Austrian physician that identified the A, B, AB, and O blood groups in 1901.
Rudolf Virchow
A German pathologist who standardized a way to preform autopsies one of two ways still used today.
** His cell theory, ("Omnis cellula e cellula") said that cells arise only from other cells.
scientific method
1. Observe a problem
2. Consider a hypothesis or possible solution.
3. Examine, test, and then analyze the evidence.
4. Determine the significance of the evidence.
5. Formulate a theory based on evaluation of the significance of the evidence
Recongnition
ability to distinguish important evidence from unrelated material(which doesn't belong)
Preservation
collection of evidence(properly clothed for the contamtination of other evidence)
Identification
use of scientific testing
Interpretation
gives meaning to all the information(meaning of the labs)(in the court)
Reconstruction
the case events( can be able to put the evidence in chronological order to present the evidence to a jury)(in the court)
direct evidence
eyewitness statements, confessions( not always the best because of biased)
Circumstantial
requires a indriect judegment or inference about what happened
***this type of evidence is not absolute proof, but does provide a general idea of what happened. It may be more reliable than direct.
Testimonial
also known as direct evidence or Prima Facie evidence( a statement made underoath that may be given)
Physical
any object or material that is relevant in a crime
Transient Evidence
temporary; easily changed or lost; usually observed by the first officer at the scene
Pattern Evidence
produced by direct contact between a person and an object or between two objects; most are in the form of imprints, indentations, striations, markings fractures or deposits.
-skid marks
Conditional Evidence
produced by a specific event or action; important in crime scene reconstruction and in determining the set of circumstances within a particular event
**head light
Transfer of Evidence
produced by contact between person(s) or object(s), or between person(s) and object(s)
Associative Evidence-
items that may associated a victim or suspect with a scene or each other; ie, personal belongings
class evidence
common group of objects or persons
example: blood type
Individual
can be identified with a particular person or source(can isolate to one and only source) example: blood DNA
Means�
person has the ability to do the crime
Motive
person has a reason to do the crime
Opportunity
person had the ability to be at the crime
Triangulation
uses two points at the crime scene to map each piece of evidence
Coordinate or grid-
divides the crime scene into squares for mapping.
Baseline
set a north/south line and measures each piece of evidence from this line.
Druggist Fold
is used with larger pieces of paper folded around larger items to hold trace evidence in place. These are then placed insider other containers such as paper bags, plastic bags, canisters, packets and envelopes depending on the type and size of the evidence.
chain of custody
A written record of all people who have had possession of an item of evidence.
Sir Edward Henry
He devised a workable classification system for fingerprints
The Bertillon System
developed the first truly organized system of identifying individuals in 1883.
He believed that everyone could be distinguished from one another by key measurements of their body.
These measurements became known as berillonage.
Dactylosocopy
the study of fingerprints
Arch fingerprint
They do NOT have type delta or cores
Plain Whorl
This print has 2 delta's and therefore it is a __________
Double loop whorl
accidental whorl
comparison
Generally, criminal courts will accept 8 to 12 points of similarity.
IAFIS
The Automated Fingerprint Identification System--a computer system for storing and retrieving fingerprints
visible fingerprints
Made by fingers touching a surface after the ridges have been in contact with a colored material such as blood, paint, grease, or ink.
Plastic Prints
Ridge impressions left on a soft material such as putty, wax, soap, or dust.
Latent Prints
are those that are "hidden" and are not visible to the naked eye. These prints consist only of the natural secretions of human skin and require treatment to cause them to become visible.
accidentals
are marks made on the soles of the shoes that would make the print unique
biometrics
*Use of some type of body metrics for the purpose of identification.
--controls entry or access to computers or other structures; identifies persons for security; helps prevent identity theft or controls social services fraud
testability
A critical evaluation process that supports or refutes a hypothesis
types of handguns
-revolvers
-pistols
types of Shoulder guns
-Rifles
-Shot Guns
tool mark
Features imparted on an object by the contact and force exerted from a tool.
-impressed
-striated
caliber
Diameter of the bullet, specifically the projectile, commonly called the slug.
class characteristics
General and/or measurable features of a specimen which indicate a Restricted group source. They result from design factors, and are therefore determined prior to manufacture.
Individual Characteristics
Marks or features produced by the random imperfections or irregularities of tool surfaces. These characteristics can be used to individually associate a tool to a toolmark.
-from abuse
-wear from use also
inconclusive
If the quality and character of the toolmark are lacking, an examiner may not be able to make an identification or elimination.