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Chapter 3: Recording the Crime Scene
Terms in this set (55)
Why is recording the crime scene so important?
- useful during the subsequent investigation
- recordings are also presented at trial to give the condition of the scene and the location of physical evidence
- memory aid
What are the 3 main methods of crime scene documentation?
When should note taking begin?
When the investigator is contacted and requested to report to the crime scene
How should crime scene notes begin?
- identity of person who contacted investigator
- time of contact and arrival at the scene
- prelim case info
- personnel present on arrival and those being contacted
What should crime scene notes contain?
- make notes on many aspects of scene in its original condition during initial walk-through
- personnel log
- all observations made by investigator
- time that observations were made (24h clock)
- which personnel was given which task at the scene
- whether evidence is in its original position or not
How should crime scene notes be formatted?
- uniform and consistent layout
- notes should be written as observations are made and NOT left to record from memory at a later time
- in a bound notebook in blue/black ink
What is the benefit of using audio tapes to record crime scene notes?
- leaves the hands free to process the scene as the notes are taken
- tape recordings must eventually be transcribed to a written document
What is the protocol for recording audio crime scene notes?
The recording must remain pertinent to the crime scene only - no extra side conversations should be occurring.
What are the benefits of photography at the crime scene?
1. Shows layout of the crime scene
2. Shows position of collected and uncollected evidence
3. Shows POV of suspects, victims, witnesses
4. Shows original condition of items of evidence at the scene
5. Produces a high-quality image that eliminates ambiguity so that everyone viewing will be able to see what happened at the crime scene
Definition: digital photography
A light sensitive microchip captures light on each of millions of tiny picture elements (pixels). The light is recorded on each pixel as a specific electric charge which is read by the camera as image info, which is stored as a file on a memory card
What is the minimum number of megapixels wanted for forensic photography?
What is the most commonly used camera at crime scenes?
Single-Lens Reflex (SLR) or Digital Single-Lens Reflex (DSLR)
What are the benefits of SLR and DSLR cameras?
- allow for use of various accessories like lenses, filters and flashes
- manual adjustment of camera settings (aperture, shutter speed) that affect image quality
- can be modified to take infrared and UV images
When would a normal lens be used?
- most crime scene photos, can show as much area as half a wall
- evidence photos at standard distances
- good for when evidence doesn't have very small details
- capturing close-up image of distant object or subject (zooming)
- photos of wide objects as it captures more detail to the left and right of the center of the structure than a normal lens
- very close photos and good detail required
- photos of fibers, tool marks (very fine details)
- allows for normal, wide-angle and telephoto photos without changing the lens
- not used as often because quality is decreased
Measure of the diaphragm opening through which light enters the camera and is allowed to reach the microchip
How is the aperture adjusted?
- via the f-stop
- lower f-number settings allow for a wider aperture and more light to be allowed in
Definition: shutter speed
Length of time the microchip is exposed to light
Definition: depth of field
Amount of area in the foreground and background of an in-focus photographic subject that's also relatively in focus
Light falling on an object in a photo
Definition: colour temperature
Measure of the "degree of whiteness" of a source compared to perfect white light
- hot = bluer hue
- cold = red-orange hue
Direct reflective lighting
Flash is attached to camera or placed 90 degrees to the plane of view providing high contrast but may show light reflectance into the photo
Aimed at 45 degrees to the plane of view to minimize reflectance
Flash is placed at an angle less than 45 degrees to show greater detail by created shadowing effect
Block one specific colour of light from reaching the microchip, making areas of that colour appear lighter in the photo
Allow only a small range of wavelengths of light to reach the microchip and block all others
What are useful features of a tripod?
- independently adjustable legs suitable for uneven terrain
- a bubble level to ensure 90 degree images of evidence
Definition: Crime scene photo log
Detailed log of each photo taken at crime scene and is kept by crime scene photographer
What should the photo log include?
- case number
- type of scene
- location of scene
- description of camera and lenses being used
- photographer's name and title
What does the log record for each photo?
- date/ time photo was taken
- location of picture
- f-stop and shutter speed settings
- lighting used and lighting angle
- brief description of subject of the picture
What is the most important prerequisite for photographing a crime scene?
It should be in an unaltered condition
What is the sequence that should be followed for photography?
- should be done in a logical succession and as completely as possible
- overall scene
- work down to individual pieces of evidence
- entire scene and surrounding area including entry and exit points
- taken from outside borders of scene and from various angles
- must show body's position and location relative to entire scene
An object recorded in multiple overview photos to help visually piece the scene together
- shows layout of smaller significant areas of crime scene
- taken with evidence markers in place to show spatial relationships between and among pieces of evidence in greater detail than overview photos
- taken last and show greater detail of individual objects or evidence
- taken at 90 degree angle to object, with and without evidence markers and scales
- scales should be placed as close to the evidence as possible without affecting it
- surface underneath body should be photographed after removal
- use of external lighting/ painting with light
- photos should be taken again during daylight hours
- needs photos of neighbourhood, points of entry and exit, all walls, floors and ceilings
- start broad and then work closer
- requires location of photos to be recorded by GPS or measurements from landmarks
- may include aerial photos
- photos of point of fire's origin and use of special equipment or techniques to provide max contrast in photos of charred areas
- photos of crowd outside scene
Sexual assault photos
- overview photos of scene and surrounding area
- photos of all wounds and clothing while showing discretion to victim
- overview photos taken to show relative position and direction of impression
- oblique lighting to show details and a scale to later create a 1:1 scale photo to compare to footwear or tire samples
- photos of all pertinent stains and determined area of convergence or area of origin
- bloodstains treated with luminol photographed in complete darkness
Latent fingerprint photos
- photos with 1:1 scale using special latent fingerprint camera or regular camera fitted with an adapter
- black and white film used to show greater contrast
What are the advantages to digital photography?
1. Increased pace of investigation
2. Ability to observe images immediately after taking them ensures images are clear and show best possible detail
3. Resolution available can exceed 6 megapixels
4. Electronic stitching of images to produce panoramic crime scene photos
What are the disadvantages of digital photography?
1. Can be easily manipulated through computer software
2. Photographer should be conscious of file format in which crime scene images are saved - should be saved as a lossless file
How do law enforcement agencies ensure the admissibility of digital crime scene photos?
1. Developing standard operating procedures that must be followed
2. Saving images to writable disks by lossless compression
3. Saving enhanced or altered images as separate files
4. Keeping a detailed and accurate photo log
5. Submitting testimony from the crime scene photographer as to the accuracy of the digital images
What is the protocol for videotaping crime scenes?
- must include overview, medium-range and close-up images
- narrated crime scene video combines photos and notes
What is the purpose of crime scene sketches?
- clearly show layout of crime scene
- illustrate relationship in space of all significant items and features
- clarify objects and features already described in notes or shown in photos
- show measurements over long distances and topography of outdoor scenes
- depict possible paths of entry, exit and movement through the scene
- demonstrate whether the account of victim, suspect or witness is feasible
What should the rough crime scene sketch include?
- created at crime scene
- title block w/ info on case, crime scene and person creating sketch
- legend with identity and dimensions of objects in sketch
- compass pointing north
- body containing the sketch itself
How should one create a crime scene sketch?
1. Define boundaries of sketch - walls for indoor scenes. Ensure that area within boundaries contains all pertinent objects and evidence
2. Establish points from which to measure locations of objects and evidence - should be fixed
3. Walls or boundaries should be drawn in first, leaving as much room as possible for contents. If walls are used then dimensions should be recorded
4. Measurements should be taken from fixed points to pieces of evidence first. Distances must be accurate and made with measuring tape and verified by 2 people
What is the current standard method for finished crime scene sketches?
Computer-aided drafting (CAD) programs
THIS SET IS OFTEN IN FOLDERS WITH...
Chapter 1: Introduction
Chapter 4: Collection of Crime Scene Evidence
Chapter 5: Physical Evidence
Chapter 17: Document Examination
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