Forensics Flashcards
What is the locard exchange principle?
Whenever two objects come into contact, there will be an exchange of materials.
What are the forensic principles?
Scientifically associate the suspect with the victim or crime scene?
What are the forensic data bases?
Identify individuals Identify weapons Identify auto paint Identify shoe impressions Identify suspects in unsolved crimes
What are the two types of evidence?
Class evidence-May infer a general category, but not one specific item or individual (type of shoe, hair color)
Unique evidence-is identification to one specific item or individual and includes all others (finger prints, physical matches, bullets)
What is the goal of collection of evidence?
Not to lose, destroy or contaminate evidence.
What type of evidence is documented?
Document everyone who handles evidence
How do you collect the evidence?
Collect entire item-knives, clothes, seat cushion, broken glass
Swab or scrape- material off item (blood, paint, other body fluids)
Cut out- material (car seats, carpet, linoleum)
How should you package evidence?
Package all evidence separately-don’t mix
All evidence must be air-dried
Proper packaging of containers
First choice are paper bags and envelopes, paper folds and plastic bags
All evidence must be sealed-staples not accepted
What is firearm/tool mark evidence?
Firearms Bullets Cartridges/cases Shot shells/wads/ slugs Pellets Bullet holes Trajectory Gun powder residue
How do you submit evidence to a forensic lab?
Package must be sealed in container- initial and date over evidence seals- submit in person or by court approved method
Properly fill out request for device from analysis
What is a macro photograph?
You always take two- first without a scale and second with a scale to show size of object-taken less than 3feet away
All macro photos should be taken from a 90 degree angle of object-keep correct prospective
What are flash settings?
Automatic
Always off
Always on-fill flash
What are unique firearm characteristics?
Rifling bullets Breech face and firing pin Firing pin Cartridge cases Extractor and ejector
What are comparison of unique characteristics?
Bullet to firearm and other bullets
Cartridge cases to firearm and others
Shot shells to firearm and others
What is the IBS- integrated ballistics identification capabilities ?
Links bullets from different shooting scenes
Links cartridge cases from shooting scenes
Links weapons to bullets and cartridge cases
What are some tool marks-cutting tools?
Bolt cutters
Wire cutters
Vice grips
Pry bars
What is forensic screening?
Identification of blood and seman
Human or animal
What are the lab standards?
Oral swabs-4to 6 swabs
Collect from victim, suspect or others involved
What is trace evidence?
Any small or fragile evidence that can be found at the scene Hair Fibers-garments, car, ropes Paint Impression-footwear, tire marks
What are uncommon types if trace evidence?
Duct tape
Paper matches
Building materials
How do you collect trace evidence?
Collect ASAP
Avoid contamination
Package separately
Document location
What is the analysis of trace evidence?
Identification if possible source
Comparison with known standards
What are the types of finger prints?
Latent- invisible, require chemical, powder or lighting
Patent-visible, made with blood, oil, grease etc
Plastic- prints impressed to object such as soap, butter, wax
Rolled impression-an initial recording of a persons prints-Palm, hands fingers
What are some common methods to recovering latent prints?
Lighting and photographing
What are two types of powders?
Regular-black and white or silver
Magnetic- black and silver
What are the types of brushes used?
Nylon filament
Camel hair
Magnetic wand
Zephyr
What are the latent lift cards?
2inch tape
White and black lift cards
What are the techniques for photographing prints?
Lens should have no macro or close up capabilities
Use a scale
Photograph straight on
Use highest resolution possible
