SLU forensics final

expert witness

a person permitted to testify at a trail because of special knowledge of proficiency in a particular field that is relevant to the case

physical evidence

any object that can establish that a crime has been committed or can link a crime to a victim and perpertrator

circumstantial evidence

evidence that relies on an inference to connect a conclusion of like ex: fingerprint

chain of custody

a list of people who have come in contact with the evidence

miranda rights

the rights that must be said before someone is arrested, you have the right to remain silent anything you say can and will be held against you in the court of law, you have the right to an attorney

5th amendment

no person should be held to answer for a capital or otherwise infamous crime, right against self incrimination

4th amendment

prohibits unreasonable searches and seizures

class evidence

pertaining to a group of people

individual evidence

pertaining to only one person

chromotography

the separation of mixtures by a certain techniques. ex: removing colors of ink from pens

questioned document

any document that has raised an issue or an investigation

charred document

any document that has become darkened and brittle by exposure to heat or fire.

latent prints

impressions produced by the ridges on the skin known as fiction ridges

AFIS

automated fingerprint identification system, uses digital technology to store known fingerprints to help match prints found at crime scenes to those known to commit crimes

invisible prints

fingerprints made up of sweat and oil that can't be seen to the naked eye

cortex

the main body of the hair

cuticle

the scale structure covering the exterior of the hair

follicle

hair follicle, small gland that hair comes out of

medulla

a cellular column running through the center of the hair

melanin

pigment granules that give hair its color

root

the hair that is coming straight from the surface of skin and can hold DNA

Hair as Evidence

Hair can only be an individual characteristic if DNA is available. This comes from the root.

All other characteristics would be considered class, including mtDNA which can come from the shaft.

anagen

the initial growth phase during which the hair follicle actively produces hair

telogen

the final growth phase in which hair naturally falls out of the skin

pH scale

scale used to specify acidity or basicity of an aqueous solution

Frye Standard

Scientific evidence is allowed into the courtroom if it was generally accepted by the scientific community. The Frye standard does not offer any guidance on reliability

Daubert Standard

Judge is the Gate Keeper

Admissibility is determined by:
Whether the theory or technique can be tested
Whether the science has been offered for peer review
Whether the rate of error is acceptable
Whether the method at issue enjoys widespread acceptance.
Whether the opinion is relevant to the issue

Physical Science Unit

Chemistry, Physics, Geology

Biology Unit

biological screening, DNA, blood spatter

Forensic field dealing with the body

Forensic pathology

a type of applied anthropology that specializes in the changes and variations in the human skeletal for the purpose of legal inquiry

Forensic Anthropology

Forensic field dealing with bugs

Entomology

Forensic field dealing with dental records

Forensic Odontology

What is Cybertechnology

Huge field encompassing many things like cyber terrorism, sabotage etc

The Fourth Amendment

the right against unreasonable search and seizure of personal property

The Fifth Amendment

right against self incrimination

7 Parts of a forensic investigation

Recognition-ability to distinguish important evidence from unrelated material
Preservation-collection and proper preservation of evidence
Identification-use of scientific testing to identify evidence
Comparison-class characteristics are measured against those of known standards
Individualization-demonstrating that the sample is unique, even among of the same class
Interpretation-gives meaning to all the information
Reconstruction-reconstructs the case events

Transient Evidence

temporary; easily lost or changed; usually observed by the first officer of the scene

Pattern Evidence

produced by direct contact between a person and an object or between two objects; most in the form of imprints, indentations, striations

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.

Transfer Evidence

produced by contact between person (s) or object (s) , or between person (s) and object (s)

Associative Evidence

items that may associate a victim or suspect with a scene or each other

Responsibilities of the first officer

Assess the crime scene
Detain the witness
Arrest the perpetrator
Protect the crime scene
Take notes

Miranda Rights

Rights read to a person of interest so that they know they are allowed to remain quiet and have an attorney present

How is Chain of Custody Kept

-A written record of all people who have had possession of an item of evidence.
-Evidence container must be marked for identification
-Collector's initial should be placed on the seal
-If evidence is turned over to another person, the transfer must be recorded.

Individual evidence

Evidence that can be isolated to only one source

Class Evidence

Evidence that can exclude some people but only narrow it down to a group of people

difference in human hair and animal hair

-An imbricate hair cuticle is only found on humans
-Medullary index for humans is generally less than ⅓ for animals it is ½

Hair Shaft

part of the hair that sticks out of the skin

Hair root

lies below the epidermis

Hair Folicle

Structure from which the hair grows

Hair Shaft Parts

Cuticle\-- outside covering made of overlapping scales
Cortex\-- outer layer made of keratin and imbedded with pigment; also contains air sacs called cortical fusi
Gives hair its shape
Melanin is located here which is the pigment granules that gives hair its color.
Medulla\-- inside layer running down the center of the cortex

DNA found in hair with root

Nuclear DNA

DNA found in hair without root

Mitochondrial DNA

Fingerprint Minutiae

lifting finger prints with powders

adhere to both water and fatty deposits. Choose a color to contrast the background. Commonly used with flat surfaces

lifting finger prints with iodine

fumes react with oils and fats to produce a temporary yellow brown reaction. Iodine crystals sublime

lifting finger prints with ninhydrin

reacts with amino acids to produce a purple reaction. Is sprayed on things such as paper and Styrofoam

lifting finger prints with silver nitrate

react with chlorides to form silver chloride, a material which turns gray when exposed to light.

lifting finger prints with cyanoacrylate

"super glue" fumes react with water and other fingerprint constituents to form a hard, whitish deposit. Good for irregular surfaces

IAFIS

Integrated Automated Fingerprint Identification System is a national automated fingerprint identification and criminal history system maintained by the FBI

Nuclear DNA

found in nucleus of the cell, from both parents

Mitochondrial DNA

found in the mitochondria, only from mother

Directionality

direction a drop traveled in space from its point of origin

Angle of Impact

-The more acute the angle of impact, the more elongated the stain.
-90 degree angles are perfectly round with 80 degree angles taking on a more elliptical shape.
-At about 30 degrees the stain will begin to produce a tail.
-The pointed end of the blood stain faces: direction the stain was traveling

Low velocity blood spatter

-Spot diameter: mostly 4 - 8 mm
-Free-falling drops (gravity only)
-Cast off from fist, shoe, weapon
-Dripping

Medium Velocity Blood Spatter

-Spot diameter: mostly 1 - 4 mm
-Blows with weapon (e.g. baseball bat)

High Velocity Blood Spatter

-Fine mist: spot size < 0.1 mm
-Small mass limits spread to 1 m
-Some larger droplets reach further
-Gunshot, back-spatter from entry wound, forward spatter from exit wound
-High speed machinery

Point of convergence

location of the blood source, can be determined by drawing lines from the blood spatter and seeing where they all connect

Area of origin

the point at which the blow to an individual occurred; it can be determined by drawing a line from the point of convergence up to where the angle of impact intersects

How handwriting analysis can link a person to a crime

Language that is used can help to establish the writer's age, gender, ethnicity, level of education, professional training, and ideology

role of a forensic linguist in an investigation

Experts that look at the linguistic content (the way something is written) of a questioned document which can help identify a writer

evidence that can be obtained from a computer and the importance of a warrant

-Data from the computer, media on it, search history
-Need to have warrant due to the 4th Amendment

who determines an expert witness' expertise

Judge

Primary Crime Scene

the location where the crime scene took place

Secondary Crime Scene

A crime scene that is related to the primary scene but it's not where the crime exactly happened.

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.

Cadaver Dogs

dogs trained to scent a dead body

Pathologist

Pathos - Suffering or diseases
Logos - word or writing

A pathologist studies disease, its causes and its diagnosis

Manner of Death

one of five means by which someone dies

Natural
Accidental
Suicidal
Homicidal
Undetermined

Rigor Mortis

stiffness of the body that sets in several hours after death

Livor Mortis

The pooling of the blood in tissues after death resulting in a reddish color to the skin

Algor Mortis

Post-mortem cooling of the body to the surrounding temperature.

Anthropology

Provides basic identification of skeletonized or badly decomposed remains.

From a whole bone or part of a bone, the scientist may be able to determine:
Age
Sex
Race
Height
Previous trauma
Body type
Possible cause of death

Trace Evidence

small but measurable amounts of physical or biological material found at a crime scene

Toxicology

Study of poisons or the detection of foreign substances in the body that can have a toxic effect such as:

Alcohol
Industrial Chemicals
Bullets

Forensic Toxicology

Postmortem—ME or coroner
Criminal—motor vehicle accidents (MVA), assault,
Workplace—drug testing
Sports—human and animal

DNA four bases

Adenine, Thymine, Cytosine, Guanine

A pairs with

T

G pairs with

C

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

Facets of Guilt

means, motive, opportunity

Means

the ability to commit a crime

Motive

person had a reason to do the crime (not necessary to be proven in a court of law by seems to be something a jury wants to hear)

Opportunity

person can be placed at the crime

Class Blood Evidence

Blood type. If you can determine the DNA you would have individual evidence.

Circumstantial Blood Evidence

Blood stain patterns

Blood Spatter

Can be analyzed to determine patterns that give investigators clues to how a crime might have happened.

Court Testimony

given by ppl on stand

ME 1

Emily Armstrong