Crime Scene Basics- For Exam Flashcards
Who is considered the “Father of Modern Forensic Science” and coined the phase, “Every contact leaves a trace”?
Edmond Locard
Who developed a system of body measurements known as Anthropometry, as a method of identification?
Alphonse Bertillion
T/F An expert witness has knowledge a lay person would not possess
True
What would be considered a secondary crime scene?
A crime scene separate from the primary scene
What are 3 methods for documenting a crime scene?
Photos, diagrams, and notes
What is the first step in documenting a crime scene?
Taking photographs
T/F Close-up photographs should be taken at 90 degrees
True
When are mid-range photos taken?
After overall photographs are taken and before close-up photographs
What type of evidence would be photographed with a measuring device if photographing shoeprints, fingerprints, shell casings
Fingerprints and shoeprints
What are 3 forms of crime scene diagrams?
rough sketch, finished sketch, and computer aided drawing
What are 2 most commonly used methods for creating a crime scene diagram?
Baseline, Triangulation
T/F The notes taken at the crime scene can be discarded after the final report has been completed
False
Properties of evidence that can be associated with a group and not with a single source:
Class characteristics
Properties of evidence that can be attributed to a single source with an extremely high degree of certainty are referred to as:
Individual Characteristics
T/F Comparison is the process of ascertaining whether two or more objects have a common origin
True
AFIS is forensic database for:
Fingerprints
What forensic database stores information about DNA profiles
CODIS
What is the surgical procedure performed to determine the cause of death?
Autopsy
What are the 3 fingerprint patterns?
Loops, arches, whorls
Who published a textbook on fingerprints in 1892?
Francis Galton
T/F Multiple people have the same fingerprints
False
T/F The chain of custody is important for evidence
True
What pattern of fingerprint is the most common?
50% of people have loops
Which print is invisible to the naked eye?
Latent print
Super glue fuming should not be used on which of these surfaces, metal, leather, cardboard, plastic bag?
Cardboard
Powders should be used on the following, mirrors, glass, tiles or all of the above
All of the above
Which is not an example of a long gun, shotgun, pistol, rifle?
pistol
T/F Lands and grooves can be found outside of the barrel?
False
What kind of microscope is used to compare striation marks?
Comparison microscope
T/F The distance from which a gun was fired can be determined based on gunpowder residue.
True
T/F Serial Numbers can ALWAYS be recovered from guns.
False
Which areas do not retain fingerprints on a gun, barrel, revolver cylinder, edge of trigger guard.
Edge of trigger guard
T/F A tool mark is an impression, cut, gouge, or abrasion caused by a tool.
True
Name at least one other type of impression:
shoe, tire, bite mark, tool mark, and plastic fingerprint
T/F Photography and casting should be done on footwear impressions.
True
Human bite mark impressions have convicted defendants in what type of cases, robbery, homicide, rape?
Homicide and rape
Arches comprise only 5% of all fingerprint patterns in the population, what are the 2 variations of arches?
Plain and tented
What are friction ridges?
raised strips of skin found on the palms of the hands, fingertips, and soles of the feet
Only 2 areas of the body have friction skin, they are:
hands and the bottom of the feet
What are the 2 main layers of skin?
Epidermis and dermis
What color does Nynhydrin produce?
purple
What is the result of temporary destruction of ridges?
The ridges will grow back in exactly the same pattern
What is NOT considered a porous surface, tile, cloth, paper, cardboard, skin?
Tile
After successfully visualizing a latent print on an object an investigator should next…
Take a 1:1 photograph of the print
Fingerprints are formed:
During fetal development
Trace evidence consists of:
Hairs, fibers, glass, paints, and soil
Biological evidence can consist of:
blood and other bodily fluids such as spittle, semen, vaginal secretions, or any other DNA source such as bone or tissue
Fingerprints found deposited in a crime scene consist of:
98% water, 2% a combination of grease, oils, salts, and amino acids
3 basic forms of fingerprints
Latent- invisible to the naked eye
Patent- deposits of contaminants (blood or greasy marks)
Plastic- fingerprint impressions where a print has been deposited in a soft surface like wax
Evidence is defined as:
anything that tends to prove or disprove a fact in contention
What is the purpose and goal of processing a crime scene
to collect as much information and evidence as possible in as pristine a condition as possible
Why is the order of sequence of the scene processing so important?
you only get one chance to do it right
What does ALS stand for?
Alternative light source
When collecting shoe impressions at a crime scene, what are 3 physical methods used for collecting the impression?
casting, gel-lifts, electro-static lifter
Bloodstain pattern interpretation is a discipline that utilizes
biology and physics
When an individual is struck with a weapon, the object doing the striking will begin to pick up blood and cast it off onto a surface. By examining the number of these patterns one can deduce…
How many times a person was hit
Blood droplets striking a surface and leaving well formed stains make it possible to determine what?
Direction and movement
Spill pattern
pooling of blood that spills, like spilling a drink
Expirated blood
blood blown out of an individuals nose, mouth, or wound
Void area
An absence of stains in an otherwise continuous bloodstain pattern.
Cast-off
Pattern created when blood is released or thrown from blood bearing object in motion
Transfer pattern
Pattern created when a wet surface comes into contact with a second surface
High velocity
Bloodstains produced by a force of approximately 100 ft per second or grater, such as a gunshot or high speed machinery
The goal of a crime scene investigation are to make a connection between…
victim, crime, suspect
For photography, what is the role of the shutter speed
the speed at which the shutter of the camera closes. A fast shutter speed creates a shorter exposure — the amount of light the camera takes in — and a slow shutter speed gives the photographer a longer exposure.
For photography, what is the role of the aperture
the opening of a lens’s diaphragm through which light passes. It is calibrated in f/stops and is generally written as numbers such as 1.4, 2, 2.8, 4, 5.6, 8, 11 and 16.
For photography, what is the role of ISO
ISO refers to your camera’s sensitivity to light. The higher the ISO, the more sensitive your camera sensor becomes, and the brighter your photos appear. ISO is measured in numbers.
Scientific method
- Define the problem or question
- Recognize variable/options
- Gather and weigh evidence
- Form a hypothesis, identify predictions
- Classify and organize the data
- Test predictions
- State opinion
Scientific method as per investigation
- Investigative question
- Investigative process: crime scene processing, interviews/interrogations, lab analysis, source of information, crime scene analysis
- Investigative conclusion
What is forensic science
The application of science to criminal and civil law
AFIS stands for:
Automated Fingerprint Identification System
What does CODIS stand for:
Combined DNA Indexing System
What does NIBIN stand for:
National Integrated Ballistic Information Network
