Midterm Flashcards
Francis Galton (1822-1911)
Undertook first definitive study of fingerprints and developed a methodology of classifying them for filing
Published book titled Finger Prints: first statistical proof supporting uniqueness of method, described basic principles that form the present system of identification by fingerprints
Leone Lattes (1887-1954)
Devised relatively simple procedure for determining the blood group of a dried bloodstain, immediately applied to criminal investigations
Edmond Locard (1877-1966)
Locard’s Exchange Principle: when a criminal comes in contact with an object or person, a cross-transfer of evidence occurs… Strongly believed that every criminal can be connected to a crime by dust particles carried from the crime scene
Calvin Goddard (1891-1955)
Refined techniques of bullet comparison by using comparison microscope…expertise established comparison microscope as indispensable tool of modern firearms examiner
Albert S. Osborn (1858-1946)
Developed fundamental principles of document examination- responsible for acceptance of documents as scientific evidence by the courts
authored Questioned Documents
Biology Unit
Biologists and biochemists apply their knowledge to the identification and DNA profiling of dried bloodstains and other body fluids, comparison of hairs and fibers, and identification and comparison of botanical materials such as woods and plants
Firearms Unit
Examination of firearms, discharged bullets, cartridge cases, shotgun shells, and ammunition of all types. Garments and other objects are also examined in order to detect firearm discharge residues and to approximate the distance from a target at which a weapon was fired. Also comparison of marks made by tools
Physical Science Unit
Applies principles and techniques of chemistry, physics, and geology to the identification and comparison of crime-scene evidence.
Staffed by criminalists who have the expertise to use chemical tests and modern analytical instrumentation for the examination of items as diverse as drugs, glass, paint, explosives, and soil. Responsibilities of unit may be further subdivided into sections devoted to drug identification, soil/mineral analyses, and the examination of a variety of trace physical evidence
Document Examination Unit
Studies handwriting and typewriting on questioned documents to advertise authenticity and/or source. Related responsibilities include analysis of paper and ink, as well as examination of indented writings (partially visible depressions on paper underneath the one with visible writing), obliterations, erasures, and burned or charred documents
Photography Unit
Examines and records physical evidence. May require use of highly specialized photographic techniques, such as digital imaging, infrared, ultraviolet, and X-ray photography, to make invisible information visible to the naked eye. Also aids in preparation of photographic exhibits for courtroom presentations
Trace evidence
Small amounts of evidence
Forensic pathology
Investigation or sudden, unnatural, unexplained, or violent deaths
Forensic pathologists’ (medical examiners or coroners) primary role to determine cause of death
Manners of death: natural, homicide, suicide, accident, or undetermined
Coroner vs. medical examiner
Coroner is appointed
Medical examiner is actual doctor
Varies by state (laws)
Refractive index
Speed at which light passes through
Compared by immersion method: glass immersed in liquid whose refractive index is varied until it is equal to that of the glass. This point = match point, observer will note disappearance of Becke line (bright halo near border of particle immersed in liquid of a different refractive index) and glass will seem to disappear
Class evidence
Group of objects or persons with characteristic physical evidence common to it
Narrows down to group
Ex. Soil and hair
Individual evidence
Identified as having originated from a particular person or source
Ex. Fingerprints and footprints
Expert witness
Has experience in the area being examined
When a warrantless search can be conducted
Given consent
Clear and present danger
Need to prevent immediate loss/destruction of evidence
Lawful arrest
items in plain sight are fair game
Protocol to process crime scene
1) clear the area
2) search using a systematic approach
3) photograph the evidence
4) make a rough sketch of the scene
5) make a final sketch
6) package the evidence properly
Physical properties of glass that are examined
Direct edge matching/jigsaw fit
Refractive index
Density
Cracks (radial/linear fractures made on entrance side, concentric/circular fractures on exit)
Soil comparison
Different minerals make different colors
Each layer/horizon looks different and has unique physical/chemical properties
A horizon: surface layer, usually darker, loose, crumbly, contains more organic matter, water leaches into with ease
B horizon: subsoil, light-colored and dense, contains little organic matter, materials washed from A collect in B
C horizon: parent material, layer of very few roots, low in clay, often contains pieces of rock
D horizon: bedrock, layers of solid rock
Tempered glass
Stronger, made by rapid heating and cooling causes dice to fragment into small squares when broken
Value of soil evidence
Prevalent at crime scenes
Transferable between scene and criminal
Value depends on variation at crime scene
Parts of a hair
Cuticle: outer covering, has scales
Cortex: contains pigment
Medulla: central canal, protein structure
Human vs. animal hair
Medulla in animal hair takes up most space- interior medullary index > 1/2
Stimulant
Class of drugs that increases action of the central nervous system
Ex. Amphetamines (“speed”), methamphetamines, cocaine & crack
Hallucinogen
Class of drug that causes alternations in thoughts or mood
Ex. LSD, PCP, ecstasy, marijuana
Narcotic
Class of drug that relieves pain and promotes sleep
Ex. Heroin, codeine
Depressant
Class of drug that suppresses the action of the central nervous system
Ex. [Ethly] Alcohol, glue, tranquilizers, barbiturates
Analgesic
Pain killer
Ex. Aspirin, Tylenol, Ibuprofen, Excedrin, Bufferin, Aleve
What are drug screening tests?
Nonspecific and preliminary in nature
Ex. Subjecting material to series of color tests that will produce characteristic colors for more commonly encountered illicit drugs
Stationary phase
Part of apparatus that does not move with sample
Mobile phase
Gas or liquid that carries the components
Calculating Rf
Rf = distance traveled by substance/distance traveled by solvent front
Will a polar compound travel farther in a non polar or polar solvent?
Travels further in a polar solvent
Paint chip comparison (3)
Direct edge matching
Microscopic (layers, color, sequence, thickness)
Solubility (chemical test)
Axillary
Armpit
Orbital
Eye
Frontal
Forehead
Cervical
Neck
Otic
Ear
Femoral
Thigh
Lumbar
Lower back
T.O.D body temp formula
Body temp drops 1.5 degrees Fahrenheit/hour
Regular body temperature: 98.6
Proper conclusions
Unless individual evidence, can not use word “match”; instead, “consistent with”, etc.
