Study Guide Semester 2 Final Flashcards
Forensis
Latin root, meaning forum, a public place, where in other times, senators and others debated, performed and held judicial proceedings.
The 3 facets of guilt (MMO)
Motive: person had a reason to do the crime (no necessary to prove in a court of law)
Means: Person had the ability to do the crime
Opportunity: person can be placed at the crime scene
Miranda Rights
You have the right to remain silent, anything you say can and will be used against you in a court of law, you have the right to an attorney, if you cannot afford an attorney, one will be provided for you.
Direct evidence
Firsthand observations. Ex, eyewitness accounts, video, etc.
Circumstantial evidence
Indirect physical or biological evidence that can link a person to a crime, but don’t directly prove guilt
Know the different types of Crime Lab Services.
Physical science unit, biology, ballistics, toxicology, chemistry, physics, geology, document examination, photography, latent fingerprints, polygraph, voiceprint analysis, evidence collection and engineering.
Medical examiner qualifications
A medical doctor (usually a pathologist) appointed by the governing body of the area
Coroner qualifications
an elected official who usually has no special medical training. In four states, the coroner is a medical doctor.
4th amendment
prohibits unreasonable searches and seizures and sets requirements for issuing warrants: warrants must be issued by a judge or magistrate, justified by probable cause, supported by oath or affirmation, and must particularly describe the place to be searched and the persons or things to be seized.
Crime Scene Number
yearcase# 12011401= dec, 01,2014
Photograph ranges at a crime scene
Overview, midrange, close up
Line/Strip
best in large, outdoor scenes
Grid
Basically a double-line search: effective but time-consuming
Zone
most effective in houses or buildings: teams are assigned small zones for searching
Spiral
May move inward or outward: best used when there are no physical barriers
Questioned sample
a sample that’s origin is unknown, goes by (Q)
Known sample
a sample that’s origin is known, goes by (K)
Secure, Catalog (sketch/photos), Collect evidence, Analyze evidence (SKIP THIS ONE)
Securing and Collecting Evidence
Transient evidence
Temporary, easily changed or lost
Conditional evidence
produced by a specific event or action, indirect evidence
Pattern evidence
produced by direct contact between a person and an object or between two objects
Associative evidence
something that may associate a victim or suspect with a scene or with each other
Fingerprints as class evidence
Ridge patterns (ex. whorls, loops, arches)
Fingerprints as individual evidence
Minutiae/Galton details
Latent
made visible by using chemicals, traces of sweat, oil or other natural secretions on the skin, not ordinarily visible
Patent
what’s left when you have some sort of liquid on your fingers, visible
Minutiae/Galton details
Core, ending ridge/ridge ending, short ridge, fork/bifurcation, delta, hook, eye, dot/island, crossover/bridge, enclosures, specialty, enclosure, enclosure spur
Whorls
a pattern of spirals or concentric circles, a pattern in which one of the two deltas and in at least one ridge makes a turn through one complete circuit
Loops
a pattern in which one or more of the ridges enter on either side of the impression, recurve, touch or pass an imaginary line drawn from the delta to the core and tend to go towards the same side of the impression
Arches
a pattern in which ridges form a hill
Principle of permanence
a fingerprint will remain unchanged during an individual’s lifetime
Principle of uniqueness
an individual characteristic: no two fingers have yet to be found to possess identical ridge characteristics
Natural Fibers examples
animal hair, plant seeds, fruit, stems, or leaves, and minerals
Animal Fibers examples
cashmere, silk, wool
Plant Fibers examples
cotton, hemp, jute, flax
Synthetic Fibers examples
microfiber, nylon, polyester, rayon, and spandex
Fibers as class evidence
fibers are mass produced
The role of statistics in fiber analysis
they help to narrow down the source, used to determine the discriminating ability between fibers of different colors and chemical compositions
Where is the DNA found in a hair?
The root contains nuclear DNA. The hair shaft contains abundant mitochondrial DNA, inherited only from mother
Homozygous
having inherited the same versions (alleles) of a genomic marker from each biological parent
Heterozygous
A term that describes having two different versions of the same gene
Genotype
the genetic makeup (i.e. the combination of alleles for each particular gene
Phenotype
the physical traits exhibited by an organism (observable)
What is plasma?
a liquid suspending other blood components
What are platelets?
aids in blood clotting and the repair of damaged blood vessels
What are red blood cells?
(Erthocytes), carries oxygen to the body’s cells and carbon dioxide away
What are white blood cells?
(Leukocytes), fights disease and foreign invaders and, alone, contain cell nuclei
Most common cell of blood
Red blood cells
Blood as class evidence
Blood typing (a method to tell what type of blood you have)
If a person is A+, what is the percent of the US population that has this blood type? (A=42%, Rh=85%).
.42*.85=.357(25.7%)
Blood as individual evidence
DNA profiling (the identification of individuals or samples by their respective DNA profiles)
Scalloping
a form of edge pattern, rigid edges
Cast off pattern
Shows where a person was standing (suspect/assailant), does not indicate what weapon is used
Spiking
forms around droplet edges when blood falls onto a less than smooth surface
Blood spatter patterns
Use of force to describe the blood spatter
Arterial bleeding
typically found on walls or ceilings and are caused by the pumping action of the heart
Transfer pattern
any pattern that occurs when a bloody object or surface comes in contact with another object or surface
Swipes
a “swipe” occurs when a bloody object moves across a clean surface and deposits blood on that surface
Wipes
a “wipe” occurs when an object moves through and disturbs wet blood that has already been deposited on a surface
Skeletonization
Dark ring around blood drop, starts drying at perimeter. Note: wiping thorough blood at different times gives different skeletonization
Calculations of the angle of impact for blood drops
sin-1(width/length)
tangent of answer
Blood trail pattern
shows directionality (one end if the blood drop more scalloped than the other), shows movement of the victim
Blood pool pattern
Pools of blood form around a victim who is bleeding and remains in one place. If victim is moved, may appear to be droplets or swipes/wipes connecting first location to second.
A+ blood type: can receive what blood types?
A+, A-, O+, O-
A+ blood type: can donate to what blood types?
A+, AB+
A- blood type: can receive what blood types?
A-, O-
A- blood type: can donate to what blood types?
A+, A-, AB+, AB-
O+ blood type: can receive what blood types?
O+, O-
O+ blood type: can donate to what blood types?
O+, A+, B+, AB+
O- blood type: can receive what blood types?
O-
O- blood type: can donate to what blood types?
All
AB+ blood type: can receive what blood types?
All
AB+ blood type: can donate to what blood types?
AB+
AB- blood type: can receive what blood types?
AB-, A-, B-, O-
AB- blood type: can donate to what blood types?
AB+, AB-
Blood typing
the testing of a sample of blood to determine an individual’s blood group, knowing additional proteins and enzymes in the blood sample, narrows the population group, increases the probability of identifying.
DNA/DNA structure
Stands for deoxyribonucleic acid and contains genetic information, found in chromosomes located in nucleus of cells, composed of nucleotides (a single unit), contains sugar molecule (deoxyribose), phosphate group, nitrogen containing base (A,T,G,C). Double helix- two coiled DNA strands
DNA profiling
used with a high degree of accuracy, biological evidence is examined for the presence of inherited traits. Some forensics laboratory techniques were originally developed for other purposes
Complementary base pairings
adenine will always pair with its complement thymine and cytosine will always pair with its complement guanine
Short Tandem Repeat
STR’s which are 2-5 bases in length. Shorter lengths make STR’s easier to use than VNTR’s
restriction enzymes are unnecessary; PCR allows the
amplication of the strands with STR sequences
DNA fingerprinting
Bands and widths are significant in matching samples of DNA.
Fingerprinting can match crime scene DNA with a suspect, determine maternity/paternity/relative match, eliminate a suspect, free a falsely imprisoned individual, identify human remains
Heterozygous vs. homozygous STR’s
If the inherited alleles for a given STR in an individual are identical (i.e., contain the same number of repeat units), the individual is homozygous for that STR. If the individual has inherited two different alleles for a given STR, then he or she is heterozygous for that STR.
Steps of DNA extraction
- Cells are isolated from biological evidence such as blood, saliva, urine, semen and hair
- The cells are broken to release the DNA from proteins and other cell components
- The DNA can be extracted from the cell nucleus
Steps of PCR amplification
- Denaturation (heating)
- Annealing (cooling)
- Extension
Restriction enzymes
Restriction enzymes are DNA-cutting enzymes. Each enzyme recognizes one or a few target sequences and cuts DNA at or near those sequences
Gel Electrophoresis
Bands of DNA are separated by size using electric current, DNA is mixed special enzymes, enzymes cut apart the DNA in specific places forming different sized fragments, DNA is separated within an agarose gel, an electric current is passed through the gel separating the fragments by size
Characteristics of handwriting
Line quality, spacing, size consistency, continuous, connecting letters, letters complete, cursive and printed letters, pen pressure
Characteristics of currency (U.S)
color shifting numeral (copper to green), raised printing, microprinting
Forgery
the action of forging or producing a copy of a document, signature, banknote, or work of art.
Exemplar
someone or something that is considered to be so good that they should be copied or imitated
John Dillinger
an American criminal who was perhaps the most famous bank robber in U.S history, he tried to burn his fingerprints off with acid, but the procedure wasn’t as successful as he hoped, he did robberies from 1933-1934
Frank Abagnale Jr.
Frank Abagnale Jr. was a pilot, doctor, and lawyer all before he turned 18 because he was extremely skilled at deception and persuasion. As seen in his track record, a string of arrests across the US and Europe, for car theft, fraud, and impersonation, along with several other lesser crimes, most of which he evaded.
Wayne Williams
He was convicted of two murders on February 27, 1982, after he was linked to the victims through meticulous hair and fiber analysis and witness testimony. Following the trial, the law enforcement task force concluded that there was enough evidence to link Williams to another 20 of the 29 deaths. He went to jail for life, and the Atlanta child killings stopped.
Amanda Knox
American college student Amanda Knox and her then boyfriend Raffaele Sollecito were twice convicted and acquitted in the 2007 murder of her British roommate Meredith Kercher in Italy
OJ Simpson
Simpson was tried and acquitted for the murders of his ex-wife Nicole Brown Simpson and her friend Ronald Goldman
Darlie Router
an American woman from Rowlett, Texas, who was convicted and sentenced to death for the murder of her sons Damon and Devon in 1996.
