FKA 1 Flashcards
(45 cards)
What are artifacts in digital photography
Caused by the sensor, undesirable changes to a digital image
What are the tonal ranges of a digital photograph
1) Highlight
- Bright areas within a photo that still maintain detail
2) Shadow
- Darker areas of the image that still maintain detail
3) Mid-tones
- Neither shadows or highlights; middle value of luminance
Why is the use of a flash useful in daylight
Reduce harsh shadows from strong sunlight
Fill flash can be used to illuminate dark or shadowed areas of interest
Using a digital camera, name 2 ways of correcting the white balance when the auto setting doesnt accurately record the colours of items
1) Grey card reading
2) Adjust the white balance setting to the appropriate light setting
- Incandescent, fluorescent, daylight
Formula to determine the maximum printed size to create a ‘good’ quality print of digital image
Divide the image size in pixels by 300
How do you ensure the retention of the integrity of digital photographs obtained at a crime scene
- All images recorded consecutively & continuously
- no images are ever deleted
- All images are downloaded to folder ‘originals’
- All images stored on archival quality write-once CD-R or DVD-R
- Stored in KME
To photographically record a crime scene, what minimum two standards must your digital camera be able to provide?
1) Minimum resolution of six mega pixels
2) Ability to capture RAW images
What are the standard items of PPE for safe guard at many crimes scenes
Gloves, mask, glasses, Mylar suit, booties, issued pants, long sleeves (when applicable)
List four problems that may occur if the crime scene is not properly secured or protected
1) Unknown persons may destroy evidence
2) loss of continuity of evidence
3) evidence could be hidden or removed
4) evidence may be deemed in admissible in court
Five basic patterns used to search a crime scene
1) Circle or spiral method
- beginning at a point on the perimeter, moving through the scene using a spiral pattern. Can utilize 1 to 2 persons
2) Strip/line method
- Area is divided into functional strips/lanes
- Strip: beginning at either end, searcher moves down the strip and reverses direction at the end of each strip (1-2 persons)
- Line: beginning at either end, a line of searchers moves down the line in a continuous single direction (larger group)
3) Grid method
- Similar to strip and search, area is divided into functional strips, then subdivided at 90° angles to each other. The surgery starts at the outer most strip and move up and down similar to strip method
4) Quadrant/ zone method
- variant 1: Confined spaces, areas not easily search by patterned movement. Good for vehicles, breaking down each area into a zone and label
- variant 2: Larger seen. Area is divided into quadrants/zones which can then be searched using another search method. Can assist in triangulation method of measuring locations of exhibits or items of interest by first properly staking and measuring the quadrants/zones
5) point to point
- Searcher determines what order they choose to deal with primary focal points and evidence. The path is clear to the first focal point, then immediately around it. Path is then cleared to the next focal point, so on and so forth until scene is complete
Upon arrival to a crime scene what order would you conduct the investigation
1) Take notes of location, persons present date/time
2) obtain information from investigator and conducted a survey of scene
3) photograph crime scene
4) Examine the exterior for evidence
5) Examine interior for evidence
6) Photograph the individual pieces of evidence seized
7) Prepare a report and advise investigator
What potential evidence could be obtained from the comparison of glass fragments seized from the scene and from the suspect
Can’t determine if the fragment is in the glass. It is glass, the type of glass can be determined and finally a physical match may be able to be completed
Where are glass Fragments to be sent for analysis and what main factors need to be taken into consideration
The RCMP does not except glass fragments for analysis. If a unit requires glass fragment analysis, depending on the seriousness of the offense, they would have to locate a private lab
When the point of entry is a broken window is it important to make note of how much glass is located on either side? Why?
Yes. As a pane of glass breaks, most pieces will move away from the source of impact. However, the pane will reach a point of stress where the glass failed and as a result, the pane will rebound, causing some glass particles to move towards the source of impact. These particles may end up on the suspect.
If a suspect is arrested shortly after an offence involving broken glass, what procedure would you use to collect fragments from that individual
If the suspect has hair, facial and/or arm hair, it should be combed with a clean sterile comb seated with cotton. The suspect should be standing on clean examination paper
The suspect should remove clothing over clean examination paper and once completed the paper should be secured along with cotton using a pharmacist fold
Why should the point of entry be examined first at the scene of a break and enter?
Potential for fingerprints and or DNA evidence, footwear impressions, tool marks from objects/tools used to assist in gaining entry. It is likely the suspect spent some time in this area and the most likely location where evidence
What common methods will you use regularly to document a crime scene
1) photography
- overall, mid range and close up
- With/without scales/markers
2) video
3) Sketching/measurements
4) Notes
- arrival/departure
- transient evidence (weather, sounds, smells)
- of evidence (FP, Footwear, etc)
5) Reports
What details should investigative notes contain with respect to your scene
Time, date, location, persons/officers present, witnesses, objects and areas of interest, sketch and document thoroughly all actions and observations made
What are three basic photographs associated with crime scene photography
Overall, mid range, close up
What is the purpose of mid range, evidence establishing, photography
To show items of evidence in relation to other fixed features within the immediate area of the item; they are more specific and more visible. These photos can be linked back to the overall shot to show its location within the scene
Why is it necessary for you FIS to speak with witnesses and or victims of a crime
To be able to clarify what items/injuries are present or not present to benefit the overall investigation into remain objective and unbiassed
Describe the reason it is necessary to record the environmental conditions when at the scene
Environmental conditions can cause changes to the scene, preserve or accelerate decomposition of evidence. Documenting the overall conditions upon arrival provides a record of these as ‘when found’ by the Officer
What should be marked on an exhibit when it is recovered
1) Time and date it is recovered
2) what it is
3) where it was located
4) file number
5) exhibit number
6) name and initials of recovering person
What is the benefit of using a rubber casting compound to record Tool marks
It allows a three dimensional scratch, gouge, cut or abrasion to be casted three dimensionally which can then be sent for tool Mark identification. This process can assist in identifying what type of tool may have caused the marks, complete comparison of a tool that was located to potentially identify or screw the tool in the investigation is causing the marks
