Final Flashcards by Shaun Hansen

What is the wavelength of visible light

400 nanometers to 700 nanometers

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What is fluorescence

The emission of light at a longer wavelength and lower energy by a substance which has absorbed light

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What kind of filters do we use for fluorescence photos

Two kinds of filters:
Exciter filter
Barrier filter

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What are some applications of UV light

• Search for hair, fibers, bodily fluids
• Use with fluorescent powders
• Use with dye stain –Ardrox
• Reveal bruises
• Enhance details of bite marks
• Reveal untreated fingerprints on textured surfaces

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What does LASER stand for

Light
Amplification by
Stimulated
Emission of
Radiation

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What optical density must goggles have when operating a LASER

OD4 or better

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What can blue light detect at a crime scene

• Hair, fibres, bodily fluids
• Bones, Teeth
• Bloodstains (go dark under blue light – no fluorescence)
• Untreated fingerprints on textured surfaces
• Footwear impressions
• Drugs, Paint, Grease

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What do we use fluorescence

We trigger fluorescence to:
• enhance friction ridge details
• eliminate backgrounds
• render latent impressions visible
• increase contrast between impression and backgroun

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Why do we use chemicals on impressions

• Eliminate background for better contrast
• Improve chances of finding impressions
• Quality of impressions developed with chemicals is often better than when developed with powders

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What are some factors to consider when choosing a chemical

History of the exhibit
o Dry, wet, previously wet, where it was found, etc.
• Seriousness of the offence
• Availability of chemicals, powders, chambers
• Value of item
• Potential for damage to area around item if fixed or immobile
• Substrate
• Matrix
• Time elapsed between deposition and examination
• Generally more/better quality prints developed with chemical processes vs powders

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What is the sequence of treatment for dry porous surfaces

Visual examination (with white light & FLS)
Indanedione/Zinc Chloride or DFO
Ninhydrin
Physical Developer
Vacuum Metal Deposition

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What is UV light?

Electromagnetic radiation with a wavelength shorter than that of visible light but longer than Xrays

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What are 3 main chemical dyes used during forensic examination

Ardrox
Brilliant yellow
Rhodamine 6G

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What is a fingerprint technique where metals are evaporated in a vacuum

VMD / vacuum metal deposition

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What is the technique used to remove tape on surfaces in order to examine the adhesive side for fingerprints

Un-Du
Compressed air

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What is the fingerprint technique most commonly used on dry porous surfaces

Indanedione / Zinc Chloride

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Three factors to consider when deciding on a chemical technique

History of exhibit
Seriousness of offence
Value of item
Damage to surrounding items
Substrate
Matrix
Time elapsed since deposition and development

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What is the proper chemical sequence to process a Porous Dry exhibit

Indandione / zinc chloride
DFO
Ninhydrin
Physical Developer
VMD

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What is the reference material that can be used for chemical development methods

Fingermark Visualisation manual

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What do you bring to Court when presenting your plan drawing

A ruler

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What are three things you should include on a rough sketch

Compass direction
Date
Time
Address
Reference points
Who drew sketch
Who measured

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PPE that should be worn at all times in the lab

Gloves
Goggles
Lab coat

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What information does the SDS provide

Identification of product
Hazard ID
First aid measures
Fire-fighting measures
Handling and storage
Personal protection

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What are two measuring methods for planned drawing

Baseline X/Y Triangulation

Why is it important for us to have knowledge of footwear manufacturing?

• To ensure that manufactured class characteristics are not overvalued as unique features. • Knowledge of manufactured class characteristics may assist in excluding a shoe. • Courts may put more weight on your credentials and testimony if you demonstrate knowledge of manufacturing processes.

What is texture in footwear manufacturing

Shallow pattern added to some molds: -Hand stippling (mechanical) -Acid Etching (chemical)

What are three types of outsole manufacturing

• Compression Molding • Injection Molding • Open-Pour Molding

What are three class characteristics to consider with footwear comparisons

• Tread Pattern • Size • Shape

What are four characteristics to consider for Random Acquired Characteristics with footwear

• Size • Orientation • Location • Shape SOLS

What is the preferred method for 3D footwear impressions

• BioFoam

What are the four premises of friction ridge skin development

Develop before birth Persistent except permanent scarring Unique and never repeated Patterns vary within limits

What do these number mean on tire sidewall: P225/65R17

Passenger tire Width of tire Aspect ratio (% of height) Rim diameter

Noise Treatment

The varied arrangement of different pitch lengths of the tread elements around the circumference of a tire

What are the three measurements we take for tire track evidence

Wheelbase Front track width Rear track width

What are some components of a tire tread

Wear bar indicators Grooves Ribs Sipes

What are two types of tire molds

Segmented mold Clam Shell mold

What are two methods used for an outdoor search

Zone search Line search

Why do you consider a chalk outline of a deceased person on a scene

Search the area under the body Take measurements for the planned drawing

What is hold back evidence

Information regarding the investigation that is believed to be known only by: • Suspect(s) involved in the crime • Police

Why do we take fingerprints and palm prints of deceased at an autopsy

• To identify prints at scene to the victim. • To identify the victim. • To conclude FPS file.

What kind of subject matter experts do we have access to for major crime scenes

• Bloodstain pattern analyst • Forensic entomologist • Forensic anthropologist • Forensic archeologist • Forensic pathologist

What procedure do we follow when examining a suspect

• Clothing should be seized • Undress over a clean white sheet/large paper • Catch any hair/fibers that may fall • Beware of cross contamination. • Have you been or will you be dealing with the victim or the scene

What are the two basic elements of bloodstain patterns

predictable and reproducible

What are three bloodstain pattern categories

1. Gravity 2. Transfer 3. Spatte

What is one more component of bloodstain photography from normal photography of crime scenes

Overall – Midrange – Close-up - Scale

How do we record a bloodstain scene

•Overall – Midrange – Close-up - Scale Take Photographs PERPENDICULAR to the surface. • Use a TRIPOD if necessar

What are three enhancement tools we use for blood

Amido Black Aqueous Leuco Crystal Violet (ALCV) Hungarian Red

What are two search tools for blood

Luminol or Bluestar

What samples to pathologists take at an autopsy

Toxicology and biological samples

What is FIS role at autopsy

Photography

What is recommended development process for wet glass

Moly D

What are two reasons you would use dye stain on an exhibit after treating with CA

Contrast Enhance

What does ninhydrin react with

Amino acids

three considerations when determining how to treat an exhibit with a chemical process.

Sentimental Value, Substrate, Matrix, Type of Offence, Severity of the offence, Portability, Monetary value

What is the correct process for developing prints on paper

Visual exam Indandione / DFO Ninhydrin Physical developer VMD

tire manufacturers will vary the size of the tread elements on a tire in order to reduce the sound of the rolling tire on asphalt. This pattern is referred to as:

Noise treatment

What are 3 aspects to consider when comparing randomly acquired characteristics (RACs) regarding a footwear comparison.

size Orientation Location Shape

Why is it important to have knowledge of footwear manufacturing

To ensure that manufactured characteristics are not overvalued as identifying features. Knowledge may assist in excluding or identifying a shoe as a possible source. Courts may put more weight on your testimony if you demonstrate and in depth knowledge of manufacturing-

3 important factors in fingerprint photography

• Proper exposure and illumination • Sharp focus (depth of field) • Fill the frame for maximum resolution