Module 2 Crime Scenes Flashcards
Primary Crime Scene
Where the crime actually occurred
Secondary Crime Scene
Related to the crime, but not the exact location; created by acts that follow the original crime
Macroscopic Crime Scene
Context or larger setting of a crime scene; an overall view of the larger scene
ie a murder occurring in a bathroom, the house as a whole would be macroscopic
Microscopic Crime Scene
Pinpoint setting of a crime, such as an individual room
Elimination Samples
Samples that are collected from people who enter the scene, such as paramedics or firemen
-Critical for sorting out which evidence is (ir)relevant
Walk-through
First surgery of a scene; used to determine how much of the area needs to be secured
Types of Documentation
-Note taking
-Sketching
-Photography
-Videography
-Crime scene measurement/mapping
Angles used in Sketches
Triangulation, Baseline and Polar Coordinates
Types of Geometric Search Patterns
Line, Grid, Zone, Wheel, Spiral, Link
What is the typical use of each geometric pattern search?
Link—Smaller scenes where linkage is easy to follow
Line&Grid—Large outdoor scenes
Zone—Scenes with defined zones
Wheel—Specialized;smaller scenes
Spiral—Scenes without physical barriers
Chain of Custody
A process that tracks the movement of evidence through its collection, safeguarding, and analysis lifecycle by documenting each person who handled the evidence, the date/time it was collected or transferred, and the purpose for the transfer
Control Samples
Not thought to be related to the event, but necessary for proper interpretation
Linkage of persons, scenes, or objects is based on….
Locard’s exchange principle
Duties of the First Responder include…
-Approach and enter scene
-Check for immediate threats
-Provide emergency care
-Control people at the scene
-Establish preliminary boundaries
-Document their actions
-Turn over control to lead investigator
Baseline sketching…
Uses a line between two fixed points, measuring evidence at right angles to the lines
Forensic Mapping
Practice of using laser scanners and surveying equipment to compile a crime scene map
Steps of CSI
- First Response
- Initial Assessment & Searching
- Collection & Processing
- Final Assessment
What should a first responder include when establishing boundaries?
-Primary scene
-Secondary scene(s)
-Points of entry & exit
-Places where victim or evidence may have been moved
-Any other reasonable location that the culprit engaged with
What is the purpose of a command post?
-Holding area for tools and equipment
-Rest area
-Place for sharing information, assigning tasks, and dispatching specialists
Explain the preliminary assessment
Build context:
-Speak with first responders
-Evaluate boundaries and safety needs
-Choose scene paths
Explain questions that arise during the formal walkthrough.
-What crime, if any, has been committed?
-What are the potential points of entry/exit? Are they open or (un)locked?
-Is anything damaged or out of place? Could there have been a struggle?
-What are signs of activity? ie meals, lights, tv, etc
-What are date and time indicators? ie mail, rotten food, etc
Explain what questions should be asked before scene processing.
-What areas should be prioritized?
-What tools/tests will be used?
-Do I need a specialist?
-Should different scene boundaries be chosen?
-What search method will be used?
-How should the task be divided?
Types of documentation
-Logs
-Notes
-Photography
-Sketches
-Video
What do crime scene log forms document?
-Entry/exit of every person on the crime scene
-All evidence recovered from the scene
-Photographs taken at the scene
What do crime scene notes document?
-When you were there
-What you did
-What you observed
-Who you worked with
What is important when taking crime scene photos?
-Adequate sizing
-Appropriate focus
-Adequate illumination
What are the qualities of examination photos?
-Extremely close up (macro)
-Enough details for individualization
What is the overarching purpose of a crime scene sketch?
To show the spatial relationships between evidence
What is videography best used for?
-Showing paths through a scene
Pros and cons of a zone search
Pros:
-Works well solo
-Adapts easily to small or irregular areas
Cons:
-Can be inefficient
-Mist be able to easily set zones
Pros and cons of a line/strip search
Pros:
-Good for large areas and irregular terrain
Cons:
-Needs multiple searchers for best results
-Needs at least one defined boundary
What is the technique of the link method?
-The search pattern follows a logical connection between pieces of evidence
Pros and cons of a grid search
Pros:
-Extremely thorough
Cons:
-Needs multiple people
-Time consuming
-Requires clear boundaries
-Awkward in small areas
Pros and cons of a spiral search
Pros:
-Easier to handle a scene solo
-Detects entry and exit points well
Cons:
-Awkward indoors
-Hard to follow spiral shape well
What is ALS used for?
-To filter out background light
-To sniff out biological stains, broken glass, and hair/fibers
Color testing
-Allows for quick identification of unknown substances
-Higher error rate than lab-based tests
What does fingerprint dusting do?
-Reveals otherwise invisible (aka latent) fingerprints
What is done by the end of the search?
-Mark everything that may be evidence (within reasonable suspicion)
-Photograph the context of a scene with placement markers
Three big steps in securing a scene
- Control all persons on the scene
- Identify all persons at the scene with verifiable personal information
- Exclude unauthorized personnel from the scene
Why do we wear colored goggles when using an ALS system?
-They filter out background wavelengths that would obscure evidence
-The light wavelengths being used can damage the eye
Long wave UV is used to detect
Blood, semen and saliva
What is the goal of evidence collection?
To preserve intact without contamination
What are vital parts of evidence collection?
Using gloves, forceps, and masks when handling
Test and document results
Package individually in appropriate containers
When documenting results, you should…..
Apply presumptive tests as needed
What is the purpose of appropriate containers?
Protect personnel from harm
Protect against physical damage
Protect against leakage
Fits comfortably and is the cheapest possible for the task
What are some biological fluids?
Saliva, semen, blood, urine, feces,vomit
How should biological evidence be kept?
Dark, dry, and cold
Individual stains should be collected using
Swabs, then air dried, then placed into a box
Wet stains on fabric should be stored by
Wrapping it in plain paper, packaging it in paper, then air drying it flat
Dry stains on fabric should be packaged by….
Packaging in paper
What is safe packaging for ammunition?
-Padded or wrapped
Safe packaging for burnt evidence?
-Paint cans or sealed glass
Safe packaging for documents?
-Flat envelopes with a cardboard insert
Safe packaging for hairs/fibers?
-Paper only, bindles
Safe packaging for weapons?
-Ziptied in cardboard boxes
What is done during the final assessment?
-Make sure all areas were searched
-Cross check evidence logs/packages
-Determine what was collected
-Assign final tasks
-Clean up messes
-Report hazards
-Release scene
What is chain of custody?
Chronological documentation showing the seizure, control, analysis and disposition of evidence
What happens to evidence once it’s purpose is served?
-Retained by police, OR
-Returned to owner, OR
-Forfeited/Destroyed
You find a small dry bloodstain in a suspects sweatshirt. How should it be collected for long term storage?
Place the shirt in a paper bag to allow it to breathe
How should evidence in the form of dollar bills be packaged?
-Paper envelope
-Plastic evidence bag
-Paper evidence bag
Secure physical custody means
Only one person has access to an object
LIMS
-Very expensive
-Very efficient
What usually happens to evidence if the case is a severe crime?
-Retained by police
