Chapter 2 - Crime Scene Investigations Flashcards
Relevant Evidence
Evidence that is important/relates to the case and has the ability to prove probability/improbability.
Probative Evidence
Evidence that proves or disproves something; think PROBING the question at hand.
Prejudicial Evidence
Evidence that influences people and establishes preconceived biases towards the matter at hand; think PREJUDICES.
Evidence
- Anything that is introduced as part of the trial.
- Can come in many forms such as physical, behavioral, chemical, etc).
Individual Characteristics
Features that are of a unique and specific origin with a very high degree of certainty.
Identification
- Determining the identity of an unknown substance.
- The goal is to accurately identify the material.
Comparison Analysis
- Connecting a standard reference sample from a known origin to an unknown substance with unknown origin
- Goal is to determine if the 2 samples share a common source.
One to Many Matching
Matching key features of one sample with many possible matches from a large pool.
One to One Matching
Comparing a set of features from an unknown sample with data from a singular reference sample/small group of reference samples.
Physical Evidence
- Evidence that is something material and tangible.
- Is measurable and can be observed.
Class characteristics
- Properties of evidence narrowed down into a broad, unspecific group.
- Used to generally reduce the possibilities.
Individual Evidence (categorizing)
- Categorizing evidence into unique, specific groups that match their individual properties with high probability.
- Provides more of a one-to-one connection.
Search Warrant
- An order issued by a judge that permits officers to legally conduct a search at a specific place and time for a specific reason.
- Details what items police are looking for.
- Officers can ONLY take the items listed in the warrant.
Probable Cause
The police present substantial evidence to a judge that proves the likelihood of them finding the evidence they are looking for.
The 4th Amendment
Protects citizens from unreasonable searches and seizures.
Exclusionary Rule
Evidence from an illegal search cannot be used as direct evidence in court.
Fruit of the Poisonous Tree Doctrine
Evidence obtained during an illegal search cannot be used to find more evidence.
Legitimate Expectation of Privacy
Exists in hotel rooms, personal offices, houses, the trunk of a car.
Plain View Doctrine
- Officers do not need a warrant to seize evidence that is in plain view.
- They have the right to seize items in places that are plainly visible where they have a right to be.
Azimuthal Locating
This process uses a compass arrangement to locate the evidence by measuring angles and distances to a known geographic point.
Coordinate Mapping
This technique divides the crime scene into a grid of small squares for searching.
Boundary
The border surrounding potential physical evidence.
Triangulation
The use of two fixed points in the crime scene to fix the position of the object accurately.
Chain of Custody
- The process that tracks the movement of evidence by analyzing its entire “lifecycle.”
- Documenting when it was collected, who handled it, the dates/times it’s been transferred/handled, and the purpose of each transfer.
Mincy v. Arizona
This case limited the length of time that a warrantless search was justified during emergency conditions.
Michigan v. Tyler
- In the case of an emergency, a warrantless search may be conducted (to determine the cause) for a reasonable amount of time.
- Reentries into the crime scene require a proper warrant.
First Responder
The initial emergency responder/officer to arrive on the scene.
Reference Sample
- A sample collected from a verified source.
- Examples: fingerprints, hair follicles.
4 Steps in Processing a Crime Scene
- Securing and isolating the scene
- Recording and documenting the scene-
- Searching and collecting evidence- searching for relevant evidence.
- Packaging, transporting, and storing evidence.
Securing and Isolating the Scene (#1)
- Ensuring that the scene is safe.
- Preserving the scene.
Recording and Documenting the Scene (#2)
- Documenting the crime scene with mapping, drawings, and photographs
- Triangulation, azimuthal locating, coordinate mapping, electronic methods.
Searching and Collecting Evidence (#3)
Searching for relevant evidence.
Packaging, Transporting, and Storing Evidence (#5)
- Carefully packing and removing evidence to prevent as much degradation and contamination as possible.
- Follows the chain of custody.
3 types of crime scenes
- Outdoor scene
- Indoor scene
- Conveyance scene
Outdoor Scenes
- Technicians are required to work outdoors where the area is subject to all types of weather conditions.
- Must be processed as quickly as possible.
Indoor Scenes
Technicians work in smaller, closed-in conditions.
Conveyance Scenes
- Scenes that involve some form of transportation.
- Cars, planes, trucks, trains, etc.
- Involves retracing the pathway of vehicles.
Warrantless Search
A search that occurs through well-established exceptions to the 4th amendment’s requirement where a prior warrant is required.
