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What are latent prints?
Invisible prints left by oils or sweat, made visible through powder, chemicals, or light.
What are patent prints?
Visible prints, often left in substances like blood, paint, or ink.
What are plastic prints?
Impressions in soft materials like clay, wax, or tar.
Identify the ridge characteristics (minutiae)
Ending ridge, bifurcation, dot/island, lake, hook/spur, crossover, bridge
What is an ending ridge?
Where a ridge ends abruptly.
What is bifurcation?
A ridge splitting into two
What is a dot/island?
A very short ridge, appearing as a dot.
What is a lake?
A ridge that forms an enclosed space
What is a hook/spur?
A short ridge off the main ridge
What is a crossover?
The intersection of two ridges.
What is a bridge?
A small ridge connecting two parallel ridges.
What are the class characteristics of fingerprints?
Fingerprint patterns: Arches, Loops, and Whorls.
- Ridge counts and pattern types are general class characteristics
What are the steps for collection of fingerprints?
Detection, photography, preservation
How do you detect fingerprints?
Use oblique lighting or lasers for locating latent prints.
- Powders (e.g., black, white, magnetic) for non-porous surfaces.
- Chemicals like ninhydrin (reacts with amino acids) or cyanoacrylate fuming for porous surfaces.
What does photography look like for fingerprints?
Always photograph prints in their original condition.
- Use macro lenses and scales.
What methods of preservation are there for fingerprints?
- Lift prints using adhesive tape for smooth surfaces.
- Store developed prints on backing cards labeled with case details.
How is a conclusion reached about fingerprints?
- Compare minutiae (10–16 points of comparison are standard in some jurisdictions).
- Utilize databases like IAFIS and AFIS.
How is documentation performed for fingerprints?
- Record the location, orientation, and condition of the print.
- Include sketches showing the context of print placement.
What is trace evidence?
Small materials like hair, fibers, glass, and paint that can transfer between individuals or locations.
What is impression evidence?
Imprints like shoeprints, tire tracks, and toolmarks.
What are the types of trace evidence?
Fibres, hair, glass, shoeprints
What are the class characteristics for fibres?
Type (natural or synthetic), color, weave pattern.
What are the class characteristics of hair?
Species, length, color, and cuticle pattern.
What are the class characteristics of glass?
Thickness, refractive index, fracture patterns.
WHat are the class characteristics of shoeprints?
Tread pattern, brand, and size.
What is the process of collection for trace evidence?
Use tweezers, lint rollers, or vacuum devices.
- Collect fibers directly onto tape or place them in paper folds.
What is the process of collection of impression evidence?
Photograph impressions at 90° with scales.
- Cast impressions using dental stone for footprints or tire marks.
How is trace evidence preserved?
- Store fibers or hairs in sealed envelopes.
- Protect glass fragments with rigid containers.
How is trace evidence identified and processed?
- Microscope analysis for fibers and hairs.
- Comparison of toolmarks or impressions using overlay techniques.
How is trace evidence documented?
- Record measurements of impressions.
- Document locations with sketches and wide-angle photos.
What is serology?
Study of bodily fluids like blood, semen, and saliva.
What is DNA profiling?
Identifying individuals through genetic material.
What is touch DNA?
DNA obtained from skin cells left on objects.
What are the class characteristics of bodily fluids?
- Blood type (A, B, AB, O).
- General enzyme or protein markers
What are the ways bodily evidence can be collected?
Wet evidence and dry evidence
How is wet evidence collected?
-Absorb onto sterile cotton or filter paper.
- Air-dry before packaging in paper envelopes.
How is dry evidence collected?
- Scrape gently with a clean tool.
- Avoid contamination by using gloves and clean instruments.
how is bodily evidence preserved?
- Always air-dry evidence before packaging.
- Store in breathable containers to prevent mold growth
What are the presumptive tests for bodily evidence?
Luminol, phenolphthalein (Kastle-Meyer test)
How is bodily evidence documented?
- Photograph stains before collection.
- Record measurements and spatial context.
What is impact spatter?
Caused by a force striking a blood source.
What are transfer patterns?
Impressions made by blood-covered objects.
What are the class characteristics of blood spatter evidence?
- General directionality of patterns.
- Shape and size of stains.
How is blood spatter evidence collected?
- Document the entire pattern with wide-angle shots.
- Take close-ups of individual stains with scales.
How is blood spatter evidence preserved?
- Swab blood stains for lab analysis.
- Ensure clothing or objects with stains are stored properly.
What are the methods of identification for blood spatter evidence
Angle of impact: Calculated using trig
Point of convergence: Determined the origin of the blood source
How is blood spatter documented?
Sketch the overall pattern and take overlapping photos.
What are ballistics?
Study of projectiles, firearms, and ammunition.
What are toolmarks?
Impressions left by tools on surfaces.
What are the class characteristics of ballistics?
Gun type, caliber, rifling pattern.
How are ballistics collected?
- Photograph firearms in situ.
- Use clean gloves to handle evidence to prevent contamination.
How is ballistic evidence preserved?
Keep bullets or casings in separate labeled containers.
How are bullets identified and matched?
Match striations on bullets to a firearm.
How are ballistics documented?
Include measurements and photographs of all collected items.
Define accelerants
Substances like gasoline used to start fires.
Define blast marks
Patterns left by explosions.
how is fire evidence collected?
- Collect debris samples from areas with suspected accelerants.
- Photograph fire patterns and blast areas.
How is fire evidence preserved?
Store debris in airtight containers for chemical analysis.
How is fire evidence used?
Test for chemical residues in a lab.
How is fire evidence documented?
Photograph all burn patterns and debris.
What camera equipment should be used for any photography?
- Use a digital single-lens reflex (DSLR) camera for high-resolution images.
- Equip the camera with macro lenses for detailed close-ups and wide-angle lenses for overall scene documentation.
- Always use a tripod for steady shots, particularly in low light.
- Utilize an external flash or additional lighting sources for accurate illumination.
In what order are photos taken in the crime scene?
Overview photos, midrange photos, close-up photos
What are overview photos?
- Capture the scene as a whole, showing its location and orientation.
- Include entry and exit points, landmarks, and any contextual details.
What is a midrange photo?
Focus on groups of evidence or specific areas of interest to establish their relationship to the scene.
What are close-up photos?
- Use macro photography for individual pieces of evidence, ensuring fine details are visible.
- Include scales or rulers in at least one photo for size reference.
How should lighting be utilized?
- Use oblique lighting (light from an angle) to enhance textures, such as fingerprints or footprints.
- Employ alternate light sources (ALS), like UV or blue light, for detecting biological stains or latent prints.
How are photos documented?
Photographic logs
- Maintain a log recording the time, date, photographer, subject of each photo, and camera settings.
- Ensure all photographs are numbered and correlated to the evidence inventory.
What does photograph documentation look like for latent prints?
- Before using powders or chemicals, take photos under oblique lighting to enhance contrast.
- After development with powder or chemicals, photograph prints again to show enhanced details.
- Use filters or monochrome settings to highlight contrast for clear minutiae (e.g., ridges and bifurcations).
What angles should be used for fingerprint documentation?
- Always photograph from 90° above the print to avoid distortion.
- Take additional angled shots to capture surface curvature, if prints are on irregular objects.
What does photography look like for trace evidence (hair, fibres, glass)?
- Use macro lenses for extreme close-ups of fibers or hairs in situ.
- Place a dark or light contrasting background under the evidence for clarity.
- Use lighting to emphasize texture, color, and weave patterns.
What does photography look like for trace evidence (shoeprints and tire tracks)?
- Position the camera directly above the impression at 90°.
- Include a measurement scale parallel to the edges of the print.
- If the print is faint, apply oblique lighting to highlight surface variations.
How are blood spatter patterns photographed?
- Start with overview shots of the entire pattern to document spatial relationships.
- Take close-ups of individual stains with scales placed parallel to the surface.
- Capture droplets from multiple angles to calculate directionality and point of convergence.
How are stains on vertical surfaces photographed?
- Position the camera directly facing the stain to prevent distortion.
- Use a tripod and remote shutter release to avoid camera shake.
How is luminol or fluorescence photographed?
- Use a tripod for stability in low-light conditions.
- Adjust the camera’s exposure settings to capture the glow from luminol reactions.
How are firearms photographed?
- Photograph the weapon in situ before moving it, showing its exact position and orientation.
- Take close-ups of serial numbers, scratches, and marks.
How are toolmarks photographed?
- Use oblique lighting to highlight grooves and indentations.
- Photograph toolmarks from multiple angles to provide a 3D perspective.
How is the body photographed?
- Start with wide-angle shots showing the entire body and its surroundings.
- Progress to midrange shots focusing on wounds, clothing, and body position.
- For injuries, use close-ups with scales and adjust lighting to reveal details of abrasions or lacerations.
How is the body photographed after it is moved?
- After the body is moved, photograph the area underneath to document any hidden evidence.
How are burn patterns photographed?
- Capture wide shots of entire structures or rooms to document burn patterns and areas of origin.
- Take midrange and close-ups of specific damage areas, such as charred debris or explosive blast marks.
How are debris patterns photographed?
- Photograph each collection point before and after debris is removed.
- Use scales to indicate the size of burn patterns or explosive residue.
How are scales utilized for photography of evidence?
- Always include a forensic scale or ruler in at least one close-up image.
- Ensure scales are level with the evidence to maintain accurate size representation.
Why are angles important in photography of evidence?
- Avoid angled or distorted shots unless necessary for documenting irregular surfaces.
- Include compass direction markers in overview photos to establish orientation.
What is done with the photos once they have been documented?
- Save all images with embedded metadata, including timestamps and camera settings, to preserve chain-of-custody integrity.
What are the class characteristics of paper evidence?
Type of paper, ink characteristics, watermarks, printing features
What is meant by types of paper?
Weight, texture, size, and color (e.g., printer paper, cardstock, notebook paper).
What are the ink characteristics?
Ink type (ballpoint, gel, fountain), color, and consistency.
WHat are watermarks?
Design or patterns embedded in the paper during manufacturing.
What are printing features?
Fonts, alignments, or misalignments, and typeface defects.
What are the individual characteristics of paper evidence?
- Handwriting (loops, angles, pressure marks).
- Unique tears, stains, or folds.
How is the collection of paper evidence performed?
- Paper evidence is highly sensitive to contamination, folds, or tears.
- Use gloved hands or tweezers to handle documents.
- If paper is found wet, let it air-dry in a controlled environment before packaging to prevent mold.
How is paper evidence photographed?
- Before collecting, photograph documents in situ to capture their spatial relationship to the scene.
- Use flat lighting for clear imaging.
- Employ macro photography for close-ups of fine details, such as handwriting or ink.
How to ensure context is preserved for photography of paper evidence?
- If found torn, ensure all pieces are collected for potential reconstruction.
- Note nearby evidence (e.g., pens, envelopes, or stamps) that might connect to the paper.
How is paper evidence preserved?
packaging, avoidance of damage, environmental control
How is paper evidence packaged?
- Place paper items in protective sleeves or acid-free paper envelopes to prevent further degradation.
- Avoid using plastic containers for long-term storage to reduce condensation or chemical interaction.
How is damage of paper evidence avoided?
- Do not fold, bend, or staple paper evidence.
- For fragile documents, consider placing them between rigid supports (e.g., cardboard) for transport.
How is the environment controlled for preservation of paper evidence?
- Store paper in a dry, temperature-controlled environment to prevent deterioration or ink fading.
How is the analysis of paper evidence performed?
- Examine watermarks under a light source to determine manufacturing details.
- Conduct UV or infrared light analysis to reveal hidden writing or erased marks.
- Use chemical analysis to determine ink composition, often matching it to a specific pen or batch.
How is handwriting analyzed?
- Identify individual characteristics like stroke consistency, spacing, and slant.
- Compare questioned documents with known exemplars (samples of the individual’s handwriting).
How is paper evidence documented?
Photographs, sketches and notes, and through chain of custody
How are sketches and notes utilized for paper evidence?
- Record the location, orientation, and condition of the paper at the scene.
- Note any visible markings, stains, or unusual features (e.g., singed edges in fire cases).
