Module 3 Flashcards
When processing the scene of a death, what are some considerations prior to moving the body
1) photograph the body in situ
2) examine body visually
3) examined with forensic Lightsource
4) use bags on the hands, feet and head
5) Collect fragile evidence
Name the common bio-hazards associated with violent crime or death scenes as well as which arti-facts at the scene present bio-hazards
1) blood
2) urine
3) feces
4) saliva
5) vomit
6) infectious disease (HIV, hepatits, etc)
What is Adipocere
A gray – white coloured wax like substance as a result of decomposition of fatty tissue in deceased bodies caused by the hydrolysis of lipids. Occurs as early as two weeks or as late as two months post death, dependant on variables such as temperature/weather, items around the body (plastic) and/or burial/embalming methods
What is forensic odontology
The use of dental knowledge in identifying bite marks or unknown human remains. Teeth and bite marks can be compared against dental records of a suspect’s teeth/test impressions to identify a source or to identify a deased person. The main application is in identifying deceased individuals.
In nanometers, what is the wavelength of the visible portion of the electromagnetic spectrum
400-700 Nanometers
The term luminescence is a general term that incorporates various phenomena including thermoluminescence, bio luminescence, chemical luminesence Which in turn includes fluorescence and phosphorescence. Briefly describe what each term means
Thermoluminescence; light admission as a result of heating or radiation
Bio luminescence; light admission from a biological process
Chemical luminescence; light emission from a chemical process
Photoluminescence; light emission from absorption of light energy
- florescence; light emitted during excitation
- phosphorescence; light emitted after excitation
During the process of qualifying yourself as an expert in court defence counsel asks are you an expert in the location, development, collection, analysis and identification of fingerprints. How would you answer this?
Only a judge can deem an examiner an expert however, with training and experience in the area of crime scene examination, evidence collection and specifically, analysis, comparison and evaluation of fingerprtints I am qualified to provide an accurate opinion and therefore I am an expert in this area.
Often forensic identification personnel will make reference in the reports or during testimony to unsuitable friction Ridge impressions. During cross-examination, defence counsel asked you to clarify the expression for the court and describe what a suitable impression is. How would you clarify the expression to the court in order to reflect your impartiality
That there was sufficient information in quantity and quality to identify to a known source or to exclude
What does AFIS acconym stand for
Automated fingerprint identification system
How are latent fingerprints or physical evidence, developed at a crime scene, to be marked prior to photographing and lifting
1) circle the impression
2) assign an R or F number
3) file number
4) date
5) initials
It is likely that the ridge detail of a fingerprint which has been developed with chemistry powder can be further enhance by the application of lightning gray powder. What about the reverse?
Yes, it can work both ways. Best success with a first application of silver powder, photograph and lift the impression, use a guttural breath on the impression, then develop with chemistry powder, photograph and lift again
What method would you use to develop/enhance a fingerprint on a waxy or a oily surface
1) florescence examination
2) Sudan black
3) cyanoacrylate
4) Chemist gray powder
List 2 recommended methods of developing/enhancing latent fingerprints on plastic bags
1) cyanoacrylate, view with white light and further process with fluorescent dye stains if applicable
2) Vacuum metal deposition
If silver gray fingerprint powder is used to examine a black, plastic cash register tray, what will probably happen to the fingerprint powder when it applied
The impression will over develop and/or fill in
List two recommended methods of lifting a finger print from a very rough surface or oddly shaped surface
1) gel/rubber lifter
2) impression moulding materials
- White school style glue
- Coe-flex
Where will you locate the recommended formula for preparing ninhydrin working solution
1) recipe book for chemical solutions located in the FIS office
2) Q-Pulse; search for ninhydrin working solution
3) copy of recipes received from the Canadian police college
Which technique is recommended for developing fingerprints on wet or damp, non-porous surfaces
Small particle reagent or molybdenum disulfide
How can you intensify a week fingerprint developed with magna fingerprint powder
Guttoral breath or chemical process such as ninhydrin or DFO
Describe the cyanoacrylate fingerprint development process
Occurs in a sealed chamber in which moisture is introduced creating humidity. Cyanoacrylate is heated on an element causing it to evaporate and as a result this bapor of water/cyanoacrylate polymerizes on the sweat/sebaceous oils and appear as white friction ridges. Post processing, dye stains can be used to enhance impression further and subsequently view them with the appropriate alternate light source for the dye being used
Name five different chemical reagents that could be used to enhance fingerprints in blood
1) DFO
2) Ninyhrin
3) Amido black
4) Leuco crystal violet
5) Hungarian Red
How would you enhance a friction ridge impression, believed to be blood, on a dark colored, nonporous surface
It could be enhanced with a chemical such as acid yellow 7, VMD, CA or powders
Will cyanoacrylate fuming interfere with acid yellow seven an acid violet 17 development of a bloody impression on a nonporous surface
Yes it will prevent the dye from reaching the blood
Explain the proper procedure to conduct a presumptive test of a stain, suspected to be blood, using a hemastix and what precautions should be taken
Indirect test. Sterile swab. Drip sterile water on swab. swab a small area of the stain away from the main/Central part of stain. Place swab on hemastix. Note result. If swab is taken subsequently, note on the envelope that indirect hemastix test was conducted. New gloves should be worn between each swab and examiner should wear a mask.
What are the three main categories of bloodstains encountered a crime scenes
1) gravity
2) Spatter
3) Transfer
List seven factors that may be determined by the analysis of blood stains
1) Point of origin
2) position of victim
3) Direction of impact
4) movement of person shedding blood
5) movement of person after incident
6) Number of impacts by object
7) Object/source distance
In a scene where you suspect blood has been cleaned up, prior to any chemical use, how would you conduct your visible examination and where
Begin with white light and florescence light source examination in areas where blood may have been missed when the cleanup was conducted (furniture, walls, ceilings, clothes, cracks of floors, etc.)
How is infrared photography helpful in documenting bloodstain patterns on some surfaces
It can be useful on dark or multicolour surfaces where the blood is not visible with white light alone
Is Luminol a presumptive test for blood
Yes
Name three basic types of construction used to manufacture tire
1) Radial
2) bias ply
3) bias Belted
Name seven basic components of the modern radial tire
1) tread
2) bead (heal/toe)
3) plies
4) belts
5) sidewall
6) shoulder
7) cap
In a forensic tire examination it is important to know whether a tire was manufactured before or after the date of offence for which the tire is alleged to have been involved.
Which numbers represent which from this serial number.
DOT PDL9 BYC 4405
DOT = meets/exceeds DOT standards
PD = Manufacturer’s location
L9 = Tire size number
BYC = Optional manufacturer numbers
4405 = date: 44th week of 2005
What is meant by the term mold rotation or mold offset
When the top and bottom halves of a tire mold or misaligned or offset leaving a defect or imperfection in the tire
Name two annual publications which can assist in identifying possible automotive tire brand
1) tire guide Inc.
2) Who makes it? And where? Directory
List three of the five factors that may cause irregular or accelerated vehicle tire wear
1) over/under inflation
2) incorrectly balanced
3) toe is in/out
4) camber out of alignment
An integral part of the forensic analysis and comparison of a vehicle tire impression is the identification of the noise treatment. Explain the term and it’s significance to the analysis
A technique of positioning geometric shape tread elements in a varied arrangement on a radial tire in a manner in which the pitch of each element is positioned to reduce road noise. The noise treatment pattern can assist in narrowing the search of the area of the tire for the purposes of comparison as it is not repeated throughout the radial tire circumference
A vehicle tire impression has been linked to a crime scene. Research indicates that the tire with that particular tread pattern is manufactured by Goodyear but the second suspect vehicle has a Moto master tire with the same tread pattern. How could this occur.
1) Goodyear made the tires for Moto master
2) Goodyear sold molds to Moto master
What is the recommended procedure to measure the wheelbase of a vehicle using only it’s tire tracks
From the leading edge of the front tire to the leading edge of the back tire
Explain the procedure to determine the track with of a vehicle based on its tire marks which have been left in the dirt
Measure from the centre of the tire tread to the centre of the tire tread of the front and rear sets of tires
To avoid damaging a three dimensional impression in snow, when using liquid sulphur as a casting medium, what is the most critical time prior to pouring
When the Sulphur begins to cool
What concerns were raised by the NAS committee pertaining to friction ridge examination and more specifically ACE-V methodology
- that ACE-V is a broadly stated framework for conducting friction ridge analysis - too broad to ensure repeatability and transparency
- this framework is not specific enough to qualify as a validated method for this type of analysis
- does not guard against bias; up to the examiner to remain objective
- does not guarantee that two analysts following it will attain same result
According to the PCAST report what two Black box studies validate the ACE-V process
1) FBI/Noblis Black box study
2) Miami Dade black box study
According to the OSAC response to the PCAST REPORT, what is the correct false positive rate in the Miami Dade black box study
0.19 %
What is cognitive bias
An individuals construction of reality not based on factual input. Biases may sometimes lead to perceptual distortion, inaccurate judgment, illogical interpretation
What is meant by adequate documentation
The documentation of the conclusions and reasoning of an examiner in a transparent manner. The documentation should be sufficient in detail so that another examiner could understand the basis for which the conclusion was made and be able to re-create the process taken.
What conclusions were drawn from the 2011 FBI and Noblis corporation study into error rates
False positive rate 0.1%
False negative rates 7.5%
What is meant by inter-examiner agreement
The process of two examiners reaching the same conclusion on the same fingerprint comparison
What is meant by Intra-examiner agreement
The process of an examiner consistently reaching the same conclusion on the same fingerprint comparisons
Examiners repeated _________% of their identification decisions
89.1%
What is meant by sufficiency?
Whether or not there is sufficient quality and quantity of friction ridge detail to continue on to comparison
Stokes Shift
The difference of wave length of light between excitation light…and light emitted as a result of excitation.
Think of UV light used on ardrox. The green light emitted as a result of being hit with UV is a longer wavelength of light and the difference between excitation light and emitted light is the stokes shift.
What is confirmation bias
Tendency to search or interpret information in a manner that supports one’s preconceptions.
An example would be bias from the known because you’re comparing the known to the unknown
What is contextual bias
The effect of information or outside influences has on the evaluation and interpretation of data.
An example would be GIS giving you arrest prints from a suspect and saying “he’s the guy it must be him”
Dysplasia is a medical condition of friction skin. What is the origin of this medical condition?
A medical condition which occurs during the formation of friction ridges resulting in disassociated ridges.
Ridge units that did not form friction ridges due to a genetic cause. Abnormal development of cells within tissues.
Question
Reasons to experiment with fingerprint forgeries
Allows an examiner the ability to distinguish between real and forged impressions
Fingerprint moulds and transfers
- unexplainable voids
- inconsistencies with clarity
- too many consistencies with multiple impressions of same mould
- distortions not consistent; smearing, but no lateral or rotational movement
- distortion not consistent with the substrate the impression was transferred from or on to
- inconsistencies of foreign information, such as geometric shapes not consistent with the substrate
Ability to determine a forgery in an investigation can prove a person’s innocence.
Dr William BABLER
1980-present. Dr Babler researched the prenatal morphogenesis of dermatoglyphic traits of friction ridge skin specifically relate to birth defects and their implications on ridge development. He testified at the Daubert hearings.
8 components of the tire tread
- groove
- notch
- rib
- rib element
- lug
- sipes
- noise treatment
- bead
- bead heel
- beed toe
- sidewall
- cap
- shoulder
- plies
- belts
- liner
What are the databases are searched when DNA is sent to the lab?
CODIS (FBI) and National DNA database (RCMP) which includes
1) Crime Scene Index
2) Convicted Offender Index
3) Victim’s Index
If file has a retention period of more than 10 years, what do you do with the digital images? What is the appropriate policy?
All photos are burned to a onc-time writable gold archival CD or DVD disc
For rention longer than 10 years, all images shall be printed Consider individual 4x6 inch photos or
‘4-up’ format of 4, 3.5x5 inch photos on a 8.5x11 inch photo quality paper
What does Forensic mean
The use of science and technology in investigations and to you bring forth facts and evidence to a court of law
ACE-V is a methodology used by the Forensic Indentification members. What is that methodology based on; what is its origin?
HUBER initially discussed ACE-V in 1959.
- purpose was to describe the philosophy of science & the correct use of the scientific method
- HUBER described hypothesis testing as it related to the comparative sciences.
- Used the words analyze, compare and evaluate (ACE) and the need for verification to describe this philosophy.
Explain the term class characteristic as related to footwear and footwear impression
In footwear these would be size, shape, style and pattern design. Predetermined nail holes and flaws in teh mold repeated in every sole or heel in the same place are also considered class characteristics if two or more shoes have them
Define the term RAC as it relates to footwear
Randomly Acquired Characteristic is a cut, tear, wear mark, randomly placed nail holes and flaws acquired during or after manufacturing but not reproduced on subsequent soles or heels manufactured
Name 3 lesser known erroneous identifications
Lana Canen was charged with murdering a 94 year old woman after her FP was found at the scene. The police officer who did the comparison had no training in fingerprint examination.
Dwight Gomas charged with robbery after an examiner identified his impression left at the scene. It was later determined to be an error by a senior examiner.
Richard Jackson was convicted of murder after 3 FP examiners testified to the identification of his FP at the scene.
