TEST 2 Flashcards
How long have fingerprints been known for?
2,000 years
Development of fingerprints
Scientists just now understanding how they are formed in the womb
10th week of gestation
As basal layers of skin grow, they’re influenced by environment around it
Arch
fingerprint pattern in which the ridge pattern originates from one side of the print and continues to the other side
Loop
a fingerprint pattern in which the ridge pattern flows inward and returns in the direction of the origin
Core
center of a loop
3 basic fingerprint pattersn
Arch (mountain)
Loop (look at your thumb)
Whorl (target)
Types of fingerprints
Patent- visible pattern left on a smooth surface when fingers coated with blood, ink, or some other substance touch a surface and transfer their print
Plastic- a three-dimensional fingerprint made in soft material such as clay, soap or putty
Latent- concealed fingerprints made visible through the use of powders or forensic techniques
Minutae
the combination of details in the shapes and positions of ridges in fingerprints that makes each unique; also called ridge characteristics
Integrated Automated Fingerprint Identification System (AFIS)
Developed by FBI
National database of fingerprints
76 million fingerprints and criminal histories
Local, state and fed agencies submit prints (though not legally req)
New Generation Identification (NGI)
Facial scans
Physical characteristics
How are latent fingerprints lifted?
Ninhydrin
Cyanoacrylate Vapor
Silver Nitrate
Iodine Fuming
Ninhydrin
Used on paper
Object dipped or sprayed w/ ninhydrin and left 24 hours
Reacts with amino acids to make prints visible- blue/purple print
Cyanoacrylate Vapor
Used on metal, plastic and glass
Sample is heated in vapor tent
Reacts with amino acids- reveals white print
Silver Nitrate
Used on wood and styrofoam
Dipped or sprayed with silver nitrate
Chloride from salt of perspiration combines with nitrate to form silver chloride
Reveals brown/black prints
Iodine Fuming
Used on paper or cardboard
In vapor tent, heat solid iodine crystals
Iodine combines with carbohydrates in latent print
BRIEFLY reveals brown-ish print that has to be photographed before it goes away
Edward Foster
Established Canada’s National Fingerprint Bureau
Trained by Scotland Yard in England
Use of fingerprints
In China since 300 BC
In Japan since 702 AD
In America since 1902
What is the first case that allowed fingerprint evid in court?
Hiller Case (1912) Creepy dude goes to the houses and molests mom then another house and molests daughter, shoots father etc
DNA
Deoxyribonucleic Acid
Double Helix of genetic material
Self replication material present in nearly all living organisms as the main constituent of chromosomes, it is the carrier of genetic info
Chromosome
Threadlike structure of nucleic acids that contains DNA in humans
Gene
Segment of DNA that codes for a trait
Electrophoresis
Method of separating molecules, such as DNA, according to size
Genome
All the DNA found in human cells
Polymerase Chain Reaction
PCR is a method of amplifying tiny amounts of DNA evid for use in investigations
DNA fingerprint
Pattern of DNA fragments obtained by analyzing a persons unique sequences of noncoding DNA
Combined DNA Index System
FBI’s computerized criminal DNA databases as well as software used to run these databases- includes National DNA Index System
What is DNA made of?
Deoxyribose Sugar and one of 4 nitrogenous bases- Cytosine, Guanine, Adenine, Thymine
Who first described DNA?
James Watson and Francis Clark in 1953 "Twisted Ladder" 46 Chromosomes in human body composed of tightly coiled DNA X, Y Chromosomes 44 Autosomes in homologous pairs
DNA Fingerprinting
Began in 1980s Dramatically impacted the field of forensic science Used to solve: -ID the guilty -ID disaster and war victims -Exonerate the innocent -Missing persons cases -Cold cases
Collection of DNA
Wear disposable gloves and change them often Disposable instruments Avoid touching areas where DNA may exist Avoid talking, sneezing or coughing on evid Avoid touching your face Air-dry evid If it cannot be dried, freeze it Put evid in new bag
Polymorphism of DNA
High variability
Located w/i non coding regions of DNA
Consist of repeating base sequences
# of differs with each individual
Short Tandem Repeats
STRs
Consisting of 50 bases
More easily recovered
FBI uses 13 core STRs
What are the top 3 ways to get DNA?
Blood
Semen
Saliva
DON’T RE-WET IF DRIED
What kills DNA evid?
sunlight
moisture
heat
Uses of DNA profiling
Many different uses
Consistent advances
Used to prove guilt
Exonerate the innocent
How does CODIS work?
In case of sexual assault where an evid kit is collected from the victim, a DNA profile of suspected perp is developed from the swabs of the kit
Forensic unknown profile attributed to suspected perp is searched against their state database of convicted offender and arrestee profiles
If there is candidate match, the lab will go through procedure to confirm match, and obtain ID of perp
What happens if tehre is a hit in the DNA database when trying to find a match?
Once match is IDed by CODIS lab involved in the match exchange info to verify match and est coordination b/w their two agencies
The match of forensic DNA record against DNA record in database may be use to est. PC to obtain and evidentiary DNA sample from suspect
Why do labs only send out hit notifications to the LE contributor?
LE agency sends crime scene evid to forensic DNA lab for analysis and production of DNA record
At time of hit, there amy not be an open or active investigation or other judicial processing and therefore the submitting LEA becomes the lab’s point of contact for hit notifications
Is any personal info relating to the convicted offenders, arrestees or detainees stores in these DNA databases?
No names or other personal identifiers are stored using the CODIS software. Only the following is stored and can be searched:
- DNA profile
- Agency identifier of submitting agency
What precautions are taken for safeguarding the info in these DNA databases?
Computer terminals/servers are located in safe space
Access to these files limited to few individuals with access to CODIS and approved by FBI
Fed law- DNA ID Act of 1994-restricts access to CJ agencies for LE purposes only
Def. is allowed access to samples and analysis performed for their own case
Unauthorized disclosure of DNA data is subject to criminal penalty not to exceed $250,000
Agglutination
Clumping of cells caused by an antigen-antibody response
Angle of IMpact
angle at which blood strikes a target surface relative to the horizontal plane of the target surface
Antibodies
proteins secreted by white blood cells that attach to specific antigens
Antigen
substance that provokes an immune response in the body
History of Blood Spatter
2500 BC- Blood letting 1628- Sir William Harvey noted continuous circulation w/i the body 1659- blood cells first viewed through microscope 1874- discovered platelets 1901- discovered blood types A, B, O 1935- First able to store blood 1971- developed antibody detection 1987-2000s- Blood screening
4 main Blood components
Plasma- 35% of total blood volume
Platelets- causes blood to clot
Red blood cells
White blood cells- only part that has DNA
Red Blood Cells
Carry gasses: Oxygen and carbon monoxide
Hemoglobin
located in RBCs; carry iron-containing proteins taht bind to oxygen in the lungs
White Blood Cells
Body locates foreign elements: bacteria, viruses, fungi and parasites
Converge on location and engulf/digest foreign elements
Blood types and Forensics
Prior to DNA profiling, blood types were used as CLASS evid
Used to exclude a person as a suspect
It is all about the antigens
Karl Landsteiner
Noticed that all blood does not mix freely- AGGLUTINATION
Rh Factor
Discovered in 1940
85% of human population has protein called Rh factor int heir RBCs
Blood that has Rh factor is designated Rh+
3 tests for blood types
Mix with A antigens
Mix with B antigens
Mix with Rh
Probabilities of blood types
A- 42% B- 12% AB- 3% O- 43% Rh+ 85% Rh- 15%
History of Blood spatter analysis
1895- Edward Piotrouski wrote the earliest reference for BSA
Baltnazard was first to research spatter pattern
1955- used to exonerate Sam Shepard
1971- physics of blood spatter used in investigations
Cohesion
Blood molecules are attracted to one another
Blood tends to stick together as it falls
Round droplets
Directionality
The shape of drop shows direction it came from
Easily determined by the pointed end of the blood
90 deg indicated by circular drops
Shapes of blood drops
As blood tavels across a surface it adheres to the surface
Cohesion means most of blood stays with original drop
Point of impact is larger than traveling edge
Trail of circular drops
Passive- indicate someone walking while bleeding
Cast off
Seen on walls and ceiling
Flying off weapons
Blood transfer
Wet bloody surface contacts a second surface with minimal lateral motion (ex: bloody footprint)
Wipe
Object moves through partially dried blood w/ lateral motion altering appearance
Swipe
Lateral transfer of wet blood from moving source onto a surface
Feathered edge indicated direction from source
Arterial Gush
Blood exiting body under pressure from an artery and striking a surface: peaks indicate heart contraction
Expired blood
Blood blown out of nose/mouth as a result of air pressure, similar to high-velocity; often w/ bubbles
Shadowing or void
Absence of blood in a pattern
Toxicology
Study of drugs, poisons, toxins, their metabolities and other substances that can harm people
Poisons
natural or manufactured chemicals that can cause severe harm
Toxins
Naturally occurring poisonous substances that living things produce
Toxicity
degree to which a substance is harmful
Areas of interest for forensic toxicology
Misused legal drugs
Illegal drugs
Environmental toxins
Brief history
Socrates- death by drinking poisonous tea
Charles Norris- NYC’s 1st Medical Examiner developed standardized techniques and testing to help determine the cause of death
Less that __% of all homicides are poisons
5
Georgi Markhov
Born 1929 in Bulgaria
Became BBC and Radio Free Europe broadcaster speaking against communism
Poisoned by ricin by KGB
Dead 4 days later
Ricin
natural toxin developed by castor beans
4 ways to be exposed to toxins
- Ingesting them
- inhaling
- injecting
- absorbing through skin
Exposures to toxins are done i what 3 ways
- Intentionally- taken as drug to treat illness and relieve pain
- Accidentally- unintentional
- Deliberately- taken as in suicide
Factors determining toxicity
Dose- how much Duration- frequency or length of exposure Nature of exposure Interactions w. other medications By-products (ex wood alcohol)
Presumptive Testing
Most is colorimetric
Microscopic examination of plant matter
Microcrystalline (small crystals that form in blood)
Gas Chromatography- Mass Spectronomy
Types of poisoning
Acute- caused by high dose over short period of time (ex cyanide)
Chronic- caused by low doses over longer periods of time (ex chemotherapy, lead, mercury)
Heavy metals
Suicides, homicides and accidental deaths have occurred throughout history due to exposure to heavy metals Arsenic- in water Lead- paint Mercury- industrial waste Stored in the soft-tissues of the body Can damage organs
Carbon Monoxide
Used in nazi death camps
Hydrogen Cyanide
used in US penal system during 1900s
Cyanide occurs naturally
Inhaled with cigs
Potassium Chloride injections
slows the heart’s electrical signals
Sodium pentothal injection
acts as depressant and slows CNS
Drugs
half of US prison pop. is there because of drug related offenses:
possession/distribution
Drugs contributed to crimes
Drug-using lifestyle where frequency of illegal activity is increasing
How much is spent each year because of effects of drug abuse (federally)?
$600 Billion
Schedule Drugs
Schedule 1: no medicinal use, high potential abuse (ex heroin)
Schedule 2: severely restricted medical use, high potential for abuse (ex cocaine, methamphetamine)
Schedule 3: Accepted medical use, moderate potential for abuse (ex Ketamine)
Schedule 4: Medical use, low potential for abuse and low risk of dependency (ex Xanax)
Schedule 5: Wide medical use, very low potential for abuse (ex: tylenol w/ codeine)
Stimulants
Highly addictive (ex meth) Increase energy and alertness Suppress appetite Users develop tolerance High blood pressure Depression often replaces euphoria Meth leads to severe weight loss, dental problems, cardiac and neurological damage)
Narcotics
Used in pain management (morphine, codeine)
Long term use can lead to addiction- can become addicted to oxycodone and hydrocodone
Symptoms include: difficulty breathing, low blood pressure, contracted pupils
Depressants
Reduce anxiety and produce sleep (ex Barbiturates and Benzodiazepines)
Highly addictive
Slows heart rate
Slows breathing rate
OFten fatal when combined with alcohol which is a CNS depressant
Anabolic Steroids
Promote tissue and cell growth and division
Chemical structure similar to testosterone
Became popular in 1930s
Side effects: increased body hair, baldness, acne, blood clotting, cancer
Not addictive- people do for results
Document Experts
Must apprentice under experienced document experts
Certifications by:
-American Board of Forensic Document Experts
-Board of Forensic Document Examiners
Handwriting
Everyone’s is unique
If document is questioned, it is compared with an exemplar
Handwriting analysis 1st questioned in 1868
-ROBINSON v MANDELL- forged will
Lindbergh case
US ct of Appeals 1999 recognized handwriting analysis as expert testimony
Factors effecting handwriting
Mood
Pace
Utensils
Medical conditions
12 Characteristics of Handwriting
- Line Quality
- Spacing
- Size Consistency
- Continuous
- Connecting letter
- Letters complete
- Cursive or printed letters
- Pen pressure
- Slant
- Line habits
- Fancy curve or loops
- placement of crosses on t’s and dots on i’s
Line quality
do the letters flow or are they erratic or shaking
Spacing
Are letters equally spaced or crowded
Size consistency
is the ratio of height and width consistent?
continuous
is the writing continuous or does the writer lift hte pen?
Connecting letters
are uppercase and lowercase letters connected?
Letters complete
Are the letters completely formed or are parts of the letters missing?
Pen pressure
Is pressure equally applied to upward or downward strokes?
Slant
left, right or variable?
Line habits
is the text on the line, above or below?
What do you do if you don’t have an exemplar?
Writing sample must be obtained
Do not inform suspect that sample will be analyzed
Dictated is more natural than copied
Avoid conscious writing effort
-Do not show the suspect the questioned or evid doc
-Do not provide the suspect guidance in punctuation or spelling
Ways of handwriting analysis
Unaided eye
Infrared Spectroscope- pressure of utensil etc
Biometric signature Pads- like at grocery store- speed, rhythm, pressure, data analyzed by expert
Computerized Analysis- Forensic Information SYstem for Handwriting (FISH)- USSS in charge
Handwriting Analysis in Court
Subject Matter Expert (SME) presents a written report Def and Pros question SME SME explains how analysis was done Explains how SME arrived at conclusion Req. strong factual evid Def will likely have its own analysis
Short comings of handwriting analysis
Quality of exemplar determines quality of analysis
Can fall victim to effect that mood, age, drugs, fatigue, and illness have on person’s handwriting
Ultimately is subjective
Certifications are important
Should be used in conjunction with other evid
Paints only a piece of the puzzle
Forgery
When accompanied by potential for financial gain, it becomes fraud
Accomplished by document alteration
Different types of document alterations
Erasure- physical erasure can be seen under stereomicroscope; chemical erasure can be seen under UV or IR light
Crossouts- use of something can expose writing crossed out
Additions- UV or IR lights can distinguish b/w ink
Burning- some inks and leads burn more slowly than paper, may be revealed under angled light
Approx how much money is cashed in bad checks each day?
$27 million
Methods of forgery
Ordering someone else’s check from deposit slip
Altering a check
Intercepting a check and altering it
Creating from scratch
Methods used to prevent check forgery
Print checks on chemically sensitive paper
Use large font size that req. more ink and makes alterations more difficult
Use high-res borders on checks that are difficult to copy
Print in multiple color-patterns
Embed fibers in checks that glow under different types of light
Use chemical-wash detection systems that change color when check is altered
Mark Hoffman
Famous forger- sole income from 1980-1985
Specialized in mormon documents and money
Counterfeiting
Typically forging of currency but can also refer to the production of fake brand name products
One of oldest crimes
COunterfeting US currency is federal felony punishable by up to 15 years in prison
USSS charged with counterfeiting investigations
Gov changes layout of bills routinely to throw off counterfeiters
Safeguards built into $100 make most expensive to produce
Detecting a counterfeit
Counterfeit detecting pen- ink causes chemical reaciton with starch; marketed as 98% effective
Bill bleaching- turning $1 into $100 bill
Additional safeguards
8 ways to spot a coutnerfeit
- portrait stands out
- fed and treasury seals
- border
- serial #s must be same color as seals
- Filaments
6.
7.
8.
14 features of authentic bills
- portrait stands out from BG
- Microprinting on security threads
- serial # color and spacing
- Letter and quadrant #
- Fed seal, no sharp points
- Treasury seal, sharp points
- filaments
- fed # and letter
- series
- check letter and face plate #
- watermark
- color shifting #
- clear disctint BG
- Clear distinct borders
