Study Guide Semester 1 Final Flashcards
Where does the word forensics come from?
derived from the Latin forensis, meaning forum, a public place, where in other times, senators and others debated, performed and held judicial proceedings.
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.
What is the first step of the scientific method as it pertains to forensic science?
- Observe a problem of questioned evidence and collect objective data.
What is the second step of the scientific method as it pertains to forensic science?
- Consider a hypothesis or possible solution.
What is the third step of the scientific method as it pertains to forensic science?
- Examine, test and then analyze the evidence.
What is the fourth step of the scientific method as it pertains to forensic science?
- Determine the significance of the evidence.
What is the fifth step of the scientific method as it pertains to forensic science?
- Formulate a theory based on the evaluation of the significance of the evidence.
What do the three part of MMO stand for and how are they used?
Motive: person had a reason to do the crime (not 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
Constitutional Law
supreme document and final authority on laws.
Statutory Law
legislative acts declaring, commanding or prohibiting something.
Common law or case law
body of law made up by judicial opinions or precedents.
Civil law
law that deals with noncriminal suits brought to protect or preserve a civil or private right or manner
Criminal law
regulation and enforcement of rights, setting the acceptable limits of conduct in society.
Equity law
remedial or preventive (restraining orders)
Administrative law
rules or laws established by agencies such as IRS, SSA, military.
Bill of rights
the first ten amendments of the US constitution, guaranteeing such rights as the freedom of speech, assembly and worship.
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.
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.
5th amendment
protects criminal defendants from having to testify if they may incriminate themselves through the testimony.
14th amendment
no state shall make or enforce any law which shall abridge the privilages or citizens of the United States, nor shall any state deprive any person of life, liberty and prosperity
Infraction
Minor offence or petty crime: penalty is usually a fine.
Misdemeanor
Minor crime punishable by fine or jail.
Felony
Major crime punishable by fines and/or more than one year in prison.
Probative
Actually proves something.
Material
Addresses an issue that is relevant to the particular crime/case.
Frye Standard
Scientific evidence is allowed into the courtroom if it is generally accepted by the relevant scientific community.
Daubert Ruling
The judge decides if the evidence can be entered into trial.
What is required to prove a criminal case in court
Sufficient evidence to prove that is more than likely than not that the defendant committed the crime.
Eyewitness testimony-why is it used and what factors can affect the testimony of a witness
Used because the criminal justice system profoundly relies on eyewitness identification and testimony for investigating and prosecuting crimes.
Factors: juries heavily influenced by eyewitness identifications, lots of innocent people convicted because of faulty eyewitness accounts.
Issues: types of questions asked by investigator, type of crime, eyewitness misidentification is the single greatest cause of wrongful convictions, playing a role in more than 75% of convictions overturned through DNA study.
Goal of Crime Scene Investigation
To recognize, document and collect evidence at the scene of a crime.
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. Ex. a blonde hair found on the hand of the murder victim with black hair.
Physical evidence
any object or material that is relevant in a crime. Ex. bullets, weapons, fibers, tool marks, etc.
Biological evidence
a type of physical evidence, consists of bodily fluids and tissues. Ex. body fluids, hair, plant parts, etc.
What is the first 7 “S” of crime scene investigation?
Securing the Scene
What is the second 7 “S” of crime scene investigation?
Speak and question the witnesses
What is the third 7 “S” of crime scene investigation?
Scanning the scene
What is the fourth 7 “S” of crime scene investigation?
Seeing the Scene
What is the fifth 7 “S” of crime scene investigation?
Sketching the Scene
What is the sixth 7 “S” of crime scene investigation?
Searching for Evidence
What is the seventh 7 “S” of crime scene investigation?
Securing and Collecting Evidence
Line/Strip Method
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
The case number
yearcase# 120111401= dec, 01,2014
The evidence inventory number
case number- evidence#_201401-01, 201401-02
Why is an evidence log completed and what types of information does the log contain?
It indicates who has each piece of evidence and why. Information- name of victim, date and time of recovery, signature of person recovering evidence, signature of witnesses to collection.
Chain of custody
Tracks the movement of evidence through its collection, safeguarding and legal considerations.
Describe how search and removal of evidence happens and which law or statute or amendment controls the search.
search and removal of evidence must be done according to the 4th amendment.
Describe the rules for a warrantless search.
Existence of emergency circumstances, need to present immediate loss or destruction of evidence search of person/property made incident to lawful arrest, search made by consent of involved parties, plain view doctrine, circumstances defined by Supreme Court
Medical examiner
A medical doctor (usually a pathologist) appointed by the governing body of the area
Medical examiner system first step
Identify the deceased
Medical examiner system second step
Establish the time and date
Medical examiner system third step
Determine a medical cause of death (the injury or disease that resulted in the person dying)
Medical examiner system fourth step
Determine the mechanism of death (the physiological reason the person died)
Medical examiner system fifth step
Classify the manner of death (natural, accidental, suicide, homicide undetermined)
Medical examiner system sixth step
Notify the next of kin
Coroner
an elected official who usually has no special medical training. In four states, the coroner is a medical doctor.
What does a coroner do?
Certifies cause of death
Rules of good photographic evidence #1
DO NOT disturb the scene
Rules of good photographic evidence #2
complete set of pictures
Rules of good photographic evidence #3
pay attention to angles
Rules of good photographic evidence #4
record all data
Why are crime scene sketches important?
Assists in interrupting and interrogating persons, preparing an investigative report, presenting the case in court.
Accurately portrays physical facts, relates sequence of events at the scene, creates a mental picture of the scene for those not present, is a permanent record of the scene.
Final sketch items requirements
Looks prettier: to scale, use a ruler, pencil only, all major furniture/items included, scale of room, lengths of items, including wall lengths, legend/key: names of furniture, evidence, symbols denoting evidence level: floor horizontal, Key: type of crime, location, sketch artists names, case number, compass indicating north, coordinates
Rectangular coordinates
Rectangular coordinates: uses two adjacent walls as fixed points as distances are measured at right angles
Baseline method
run a baseline from one fixed point to another, from which measurements taken at right angles
Triangulation
common in outdoor scenes, two fixed objects create a triangle, evidence in angle formed by two straight lines
Compass point method
uses a protractor to measure the angle formed by two lines
Cross-projection
presents floors and walls as if they were on one surface
Why are crime scene photos needed?
Testimonial evidence is faulty, admissions of guilt are not iron clad, jurors are influenced by what they can see and experience in the courtroom, photographs of the crime scene and evidence is powerful tool in bringing jury to crime scene
Natural light
light from the sun
Best use of natural light
produces different colors and contrasts based on time of day
Back lighting
creates a silhouette- light source behind object
Best use of back lighting
little value in crime scene photography
Side lighting
puts shadows on unlit side
Best use of side lighting
brings out fine texture, shadows obscure important interior details
Front lighting
light source is behind you
Best use of front lighting
best representation of most crime scenes
Alternate light source
ultraviolet, infrared, fluorescent
Galton’s contribution
Identified and named minutiae patterns. Published the first treatise on applying science to criminal investigation.
Bertillon’s contribution
Developed a system to identify people using particular body measurements. Used anthropology to identify criminals
Orfila’s contribution
Published a treatise on the detection of poisons.
Locard’s contribution
Formulated his famous principle, “Every contact leaves a trace”
James Watson and Francis Crick
discovered the DNA double helix
Landsteiner’s contribution
Identified human blood groups, helped to discover Rh factor in human blood.
What is the function of fingerprints?
All fingers, toes, feet and palms covered in small ridges, ridges help us grip objects, ridges are arranged in connected units called dermal or friction ridges, fingers accumulate natural secretions and dirt, fingers leave prints on objects we touch.
How are fingerprints formed?
Basal layer grows faster than the layers above and below it, basal layer collapses and folds to form intricate shapes.
Formed during fetal development. Fetuses develop smooth volar pads because of the swelling tissue. Around week 10, the volar pads stop growing while the hands continue to grow. As a result, the volar pad is absorbed back into te hand and during this stage the first signs of ridges will start to appear. If the ridges appear while the volar pad is pronounced= whorl. Less pronounced= loop. Nearly absorbed= arch.
Eccrine glands
secretes largely water with both salts and amino acids. Found on palms of hands, feet. Most important for fingerprints.
Apocrine glands
secretes pheromones and other organic materials. Found in axial and genetical regions.
Sebaceous glands
secretes fatty or greasy substances, sprouts a hair
Will this test make you sweat? Why?
Yes, because of stimulus responses. The chief stimuli to sweating are heat, emotion and gustatory perspiration (eating spicy food). Emotional perspirations occurs characteristically on the forehead, axillae, palms and soles.
Arches
a pattern in which ridges form a hill
What is the first type of arch in which the friction ridges enter on one side of the print and flow out the other side with a rise or wave in the center? Percentage?
Plain arch and 4%
What is the second type of arch in which two independent ridges come together and form an angle? Percentage?
Tented arch and 1%
What percent of the population has arches?
About 5%
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
What is the first type of loop in which a fingerprint or palmprint pattern consists of a loop which opens toward the ulna side of the hand (toward the pinkie)?
Ulnar loop
What is the second type of loop in which the pattern flows in the direction of the radius bone of the forearm (i.e., toward the thumb)?
Radiule/radial loop
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
What is the first type of whorl in which the pattern is the generic kind? Percentage?
Plain whorl and 2%
What is the second type of whorl in which two deltas and at least one ridge make a complete circuit? Percentage?
Central pocket loop whorl and 4%
What is the third type of whorl in which there are two separate loop formations with two separate and distinct sets of shoulders and two deltas? Percentage?
Double loop whorl and 0.01%
What percentage of the population has loops?
About 65%
What is the fourth type of whorl in which there are two deltas and a combination of two different types of patterns? Percentage?
Accidental whorl and 23.99%
What percent of the population has whorls?
About 30%
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
Patent prints: Contaminated print
2.D, visible prints transferred onto smooth surfaces by blood or other liquids
Patent prints: Plastic prints
3.D, indentations left in soft materials such as clay or wax
Latent prints
made visible dusting with powders or the use of chemicals
Dusting
a very fine powder is used that can stick oil to the fingerprint
Ninhydrin reaction
reacts with amino acids to produce a purple color
Ninhydrin surfaces
paper, tissue, clothing, porous surfaces
Ninhydrin color development
purple blue print
Silver nitrate reaction
reacts with chloride to form silver chloride, a material that turns grey when exposed to light
Silver nitrate surfaces
wood, styrofoam
Silver nitrate color development
black or reddish brown (under UV light)
Cyanoacrylate reaction
“superglue” fumes react with water and other fingerprint constitutes to form a hard, whitish deposit
Cyanoacrylate surfaces
household items, plastic, metal, glass
Cyanoacrylate color development
white print
Dusting powder surfaces
Glass, metal
Porous
having minute spaces or holes through which liquid or air may pass.
Porous examples
Sponges, wood, rubber, cork
Non porous examples
glass, plastics, metals, steel
Minutiae/Galton details
Core, ending ridge/ridge ending, short ridge, fork/bifurcation, delta, hook, eye, dot/island, crossover/bridge, enclosures, specialty, enclosure, enclosure spur
