Test 1 Flashcards
What is the definition of Forensic Science?
Is the application of science to criminal and civil laws
Who is the father of Forensic Toxicology?
Mattieu Orfila
Who devised the first definitive study of fingerprints and their classification?
Francis Galton
Who devised the first scientific study of personal identification in 1879?
Alphonse Bertillion
Who developed a procedure to determine blood type from dried bloodstains?
Leone Lattes
Who used a comparison microscope to determine if a particular gun fired a bullet?
Calvin Goddard
Who developed the principles of document examination?
Albert Osborn
Who utilized microscopy and other methodologies to examine evidence?
Walter McCrone
Who wrote the first treatise describing the application of scientific principles to the field of criminal investigation?
Hans Gross
Who was the first person to be convicted and exonerated using DNA profiling?
Colin Pitchfork
Who was the first to discover inherited variation in human DNA and characterized blood?
Dr. Alec Jeffery
Who incorporated Gross’ principle within a workable crime laboratory?
Edmond Locard
What is Locards Exchange Principle?
States that when a criminal comes in contact with an object or person, a cross-transfer of evidence occurs
What are the reasons that there has been an increase of crime laboratories?
- Supreme Court decisions in the 1960s responsible for police placing greater emphasis on scientifically evaluated evidence
- Crime laboratories inundated with drug specimens due to accelerated drug abuse
- The advent of DNA profiling
The technical support provided by crime laboratories can be assigned to five basic services:
- Physical Science Unit
- Biology Unit
- Firearms Unit
- Document Unit
- Photographic Unit
Physical Science Unit
incorporates the principles of chemistry, physics, and geology to identify and compare physical evidence
Biology Unit
applies the knowledge of biological sciences in order to investigate blood samples, body fluids, hair, and fiber samples
Firearms Unit
investigates discharged bullets, cartridge cases, shotgun shells, and ammunition
Document Unit
provides the skills needed for handwriting analysis and other questioned-document issues
Photographic Unit
applies specialized photographic techniques for recording and examining physical evidence. Some crime laboratories may offer a number of optional services
What are the 5 optional services by Full-Service Labs?
Toxicology Unit
Latent Fingerprint Unit
Polygraph Unit c
Voiceprint Analysis Unit
Evidence-Collection Unit
Toxicology Unit
Examines body fluids and organs for the presence of drugs and poisons
Latent Fingerprint Unit
processes and examines evidence for latent fingerprints
Polygraph Unit
conducts polygraph or lie detector tests
Voiceprint Analysis Unit
attempts to tie a recorded voice to a particular suspect
Evidence-Collection Unit
dispatches specially trained personnel to the crime scene to collect and preserve physical evidence
How does analyzing physical evidence require the Scientific method?
Formulate a question worthy of investigation
Formulate a reasonable hypothesis to answer the question
Test the hypothesis through experimentation
Upon validation of the hypothesis, it become suitable as scientific evidence
What are the 6 skills of a forensic scientist?
- Forensic scientists apply physical and natural science principles to analyze evidence from criminal investigations.
- They may also serve as expert witnesses in court.
- An expert witness is recognized by the court as having specialized knowledge beyond that of an average person.
- Their role includes evaluating evidence based on their expertise, which the court does not possess.
- They provide expert opinions on the significance of their findings.
- The requirement for forensic scientists to testify in court stems from the Melendez-Diaz v. Massachusetts case.
What is the Frye Standard
Frye v U.S. decision set guidelines for determining the admissibility of scientific evidence into the courtroom
How do you meet the Frye Standard?
The evidence in question must be “generally accepted” by the scientific community
Why is Frye not absolute?
The Supreme Count asserted that the Daubert v Merrall Dow Pharmaceutical case was not an absolute prerequisite to the admissibility of scientific evidence
What were the Trial Judges responsible for after the Supreme found that Frye is not an absolute standard?
Responsible as “gatekeepers” for the admissibility and validity of scientific evidence presented in their courts, as well as all expert testimony
What is the Daubert Criteria?
Guidelines offered by the Supreme Court as how a Judge can gauge scientific evidence
What are the 5 guidelines in the Daubert Criteria?
- Whether the scientific technique or theory can be (and has been) tested
- Whether the technique or theory has been subject to peer review and publication
- The techniques potential rate of error
- Existence and maintenance of standards controlling the techniques operation
- Whether the scientific theory or method has attracted widespread acceptance within a relevant scientific community
What are the services available to the law enforcement community to augment the services of the crime laboratory?
Forensic psychiatry
Forensic odontology
Forensic engineering
Forensic computer Science
What is Forensic Psychiatry?
the relationship between human behaviour and legal proceedings is examined
What is Forensic Odontology?
using teeth to provide information about the identification of victims when a body is left in an unrecognizable state and also investigates bite marks
What is Forensic Engineering?
failure analysis, accident reconstruction, and causes and origins of fires or explosions
What is Forensic Computer Science?
examination of digital evidence
When there is no formal Evidence Collection Training how else can training occur?
Lectures, tours of the lab. and evidence collection manual
What is the first responding officer to a crime scene responsible for?
- Acquiring medical assistance for injured victims
- Detaining any potential suspects or witnesses
- Securing the crime scene to the greatest extent possible
- Calling for any additional personnel needs such as other officers and/or forensic investigators
What should investigators never do at a crime scene?
Smoke, drink, eat, or litter
What does the search patten of the scene depend on?
Size and locale of the scene and the number of collectors participating in the search
Physical evidence can be anything from
Massive objects to microscopic traces
What are the three methods for crime-scene recording?
- Photography
- Sketches
- Notes
What should crime scene notes begin with?
- the identity of the person who contacted the investigator
- time of contact and arrival
- preliminary case information
- personnel present on arrival at the crime scene
How is a digital photograph made?
When a light sensitive microchip captures light of each of millions of tiny picture elements called pixels
What are the advantages of digital crime scene photography?
- Immediate image review ensures clarity and detail.
- Digital resolution exceeds 12MP, while film SLRs max at 5MP.
- Software can stitch digital images for 3D crime scene views.
What is the most important prerequisite for photographing a crime scene?
be in an unaltered condition
What are the four minimum photographs required at a crime scene?
overview, medium range, close-up, close-up with scale
Overview photographs are
Taken from outside the scene at various angles
If a body is present, capture its position in relation to the scene
Use a “visual tag” to link multiple overview shots.
Medium-range photographs are
Taken with evidence markers to show spatial relationships.
Include at least one photo of the scene’s “centre.”
In violent crimes, this is usually where the victim was found and the surrounding area.
Close-up photographs are
Take photos at a 90-degree angle, with and without markers/scales.
Place scales close to evidence without disturbing it.
After 90-degree shots, take photos from other angles.
Key close-ups include injuries and weapons near the body.
Photograph the surface beneath the body after it’s removed.
What is the Walkthrough-initial survey of the crime scene?
- Perpetrators’ point of entry and exit are located
- Indirect path is taken to the center of the crime scene
- Obvious items of evidence are located and documented
- The conditions of the scene are observed and recorded
What is the Line/Strip search pattern?
One or two investigators start at the boundary of the crime scene and search in straight lines across to the other side
What is the Grid search pattern?
Two or more investigators form a grid by searching in line patterns that overlap and are perpendicular to each other
What is a Spiral search pattern?
One investigator searches in a spiral path from the centre of the crime scene to the boundary (outward) or from the boundary of the crime scene to the centre (inward)
What is the Wheel/Ray search pattern?
Several investigators search in straight lines from the centre to the boundary (outward) or from the boundary to the centre (inward)
What is Quadrant/Zone search pattern?
The crime scene is divided into smaller sections (zones) and one or more investigators are assigned to each zone
What do all rough sketches include?
Title block with information on the case
Legend with identity and dimensions of objects
Compass showing the North direction
Body containing the sketch itself
Points of reference for objects can be shown by the distance measurements from two fixed points
What current standard method is used to create the finished sketch?
Computer-Aided Drafting (CAD)
What is used to pick up small items?
Disposable forceps
What is used for hairs, glass, fibres, and small evidence?
Unbreakable plastic pill bottles
What is used for the most trace evidence?
Manula envelopes, screw glass vials, cardboard pillboxes
What is it called when small amounts of evidence needs to be conveniently wrapped?
Druggiest fold
What should evidence from arson scenes be packaged in?
airtight metal or glass containers to prevent the loss of accelerant vapors
What happens if biological or bloodstained materials are stored in airtight containers?
The accumulation of moisture may encourage the growth of mold which can destroy evidential value
What is Chain of Custody?
a list of all persons who came into possession of an item of evidence
What is Standard/Reference sample?
Physical evidence whose origin is known, such as blood or hair from a suspect, that can be compared to crime-scene evidence
How is evidence usually submitted?
By personal delivery or by mail
What should be worn when dealing when potentially infectious material is present?
latex gloves, Tyvek-type show covers, a particle mask/respirator goggles, or face shields
The removal of any evidence from a person or from the scene of a crime must be done in conformity with….
The Fourth Amendment privileges
The United States Supreme Court has determined that search and seizure without a court-approved warrant is justified in four cases
- The existence of emergency circumstances
- The need to prevent the immediate loss or destruction of evidence
- A search of a person and property within the immediate control of the person provided it is made incident to a lawful arrest
- A search made by consent of the parties involved
What is physical evidence?
It encompasses any and all objects that can establish that a crime has or has not been committed or can provide a link between a crime and its victim or a crime and its perpetrator
What happens if an investigator cannot recognize or preserve physical evidence?
It cannot be salvaged
What is the purpose of examining physical evidence?
Identification or comparison purposes
What is the purpose of evidence examination?
Identifying the physical or chemical makeup of a substance as accurately as possible using current methods
What is the purpose of comparison analysis of evidence?
Tests and examines a suspect sample and a reference sample to see if they come from the same source
What are the two steps of the forensic comparison?
- Combinations of select properties are chosen from the suspect and the standard/reference specimen for comparison
- Once the examination has been completed, the forensic scientist must be prepared to render a conclusion with respect to the origins
What is the role of probability?
Probability is the frequency of occurrence of an event
What are Individual Characteristics?
Evidence that can be linked to a specific source with a very high likelihood is said to have individual characteristics
These are examples of____________________
1. The matching ridge characteristics of two fingerprints
2. The comparison of random striation markings on bullets or tool marks
3. The comparison of irregular and random wear patterns in tire or footwear impressions
4. The comparison of handwriting characteristics
Individual Characteristics
What are Class Characteristics?
Evidence associated only with a group is said to have class characteristics
The probability of a nylon fibre originating from a particular sweater or a paint chip from a suspect car from a hit and run is an example of______________
Class evidence
The changes of encountering two indistinguishable items of physical evidence at a crime scene that actually originated from different sources are:
Low
The contribution of physical evidence is determined___________
in the courtroom
What is a critical phases of the death investigation?
Preliminary reconstruction of events
Photographs must be taken _________ the scene is altered
Before
What is the goal of a forensic/medicolgal autopsy?
Determine cause of death and confirm the manner of death
What will tissues and organs will be retained for?
pathological and toxicological examination
Blunt force injuries
A blunt force injury, caused by an unsharpened object like a bat or pipe, can abrade tissue or cause a contusion from bleeding in ruptured blood vessels beneath the skin
Sharp force injuries
occur from weapons with sharp edges, such as knives or blades
Asphyxia
encompasses a variety of conditions that involve interference with the intake of oxygen
What is the most important factor in characterizing a gunshot wound?
The distance a weapon was fired from a target
What are the 5 categories death is classified as?
- Homicide
- Suicide
- Accidental
- Natural
- Undetermined
How can the examiner use the Algor mortis to determine the approximate time of death
Results in the loss of heat by a body as general rule the body loses heat by 1 to 1 ½ degree
How can the examiner use the Liver mortis to determine the approximate time of death
results in the settling of blood in areas of the body closest to the ground
How can the examiner use the Rigor mortis to determine the approximate time of death
results in the shortening of muscle tissue and the stiffening of body parts in the position at death
Forensic pathologists can determine the amount of ______________ in the ________________ and use it to approximate the time of death
Potassium
Vitreous humor
What is forensic anthropology?
the identification and examination of human skeletal remains
What is Forensic entomology?
the study of insects and their relation to a criminal investigation, commonly used to estimate the time of death
By determining the oldest stage of fly found on a body, entomologists can?
approximate the postmortem interval (PMI)
