Crime Scene Investigation Overview

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Questions and Answers

What is the main purpose of the chain of custody in evidence collection?

To collect evidence from various locations

To ensure evidence is accurately measured in photographs

To provide multiple views of the crime scene

To prove the integrity of evidence submitted to court (correct)

Which method requires the investigator to stand at a fixed point and sight to the evidence exhibit?

Baseline measurements

Chain of custody

Photogrammetry

Polar coordinates (correct)

What is the primary purpose of securing and preserving a crime scene?

To ensure evidence can be properly documented and admitted in Court (correct)

To enable a fast exit for first responders after their duties

To create an atmosphere of safety for the public

To allow witnesses to freely access the area

In photogrammetry, what is essential for measurement calculations?

Multiple overlapping photos from different angles Signup and view all the answers

What characterizes the inner perimeter of a crime scene?

It is the core area where the criminal act took place Signup and view all the answers

What must be recorded in baseline measurements for evidence collection?

Cardinal direction of each measurement Signup and view all the answers

Who typically assumes control of a crime scene until a crime scene investigator arrives?

A ranking officer or police supervisor Signup and view all the answers

Which of the following methods is considered the simplest but least accurate for mapping a crime scene?

Polar coordinates Signup and view all the answers

What is one of the responsibilities of a crime scene investigator?

To assess and gather evidence at the scene Signup and view all the answers

What can result from popular media representations of crime scene investigators?

Public misinformation about the investigation roles Signup and view all the answers

What is an early step in managing a crime scene?

Establishing the crime scene area Signup and view all the answers

Which of the following best describes the role of uniformed patrol officers at a crime scene?

They respond to emergencies and assume initial control Signup and view all the answers

What happens when death is known or suspected at a crime scene?

The coroner or medical examiner must be called to the scene Signup and view all the answers

Which of the following should be recorded regarding the initial walkthrough?

The identification of evidence and the team assignments Signup and view all the answers

What is the appropriate way to amend a mistake in notes taken at a crime scene?

Cross out the error with a single line and initial beside it Signup and view all the answers

What kind of information should be included in the notification information section?

Method of notification and information received concerning the crime Signup and view all the answers

Why is meticulous note-taking important in crime scene investigations?

It ensures a detailed account that can be referenced later Signup and view all the answers

What should be documented regarding the crime scene conditions?

Weather, temperature, and ground conditions Signup and view all the answers

Which detail is NOT essential when describing the scene description?

The exact demographics of the local area residents Signup and view all the answers

What information about the personnel present at the crime scene should be included?

Names and affiliations of personnel, as well as witnesses Signup and view all the answers

What is a critical aspect of the documentation of evidence at a crime scene?

Maintaining continuous documentation from start to end of the investigation Signup and view all the answers

What is the purpose of a crime scene sketch?

To provide a permanent record of size and distance relationships Signup and view all the answers

What must every crime scene photo include?

A photo log documentation Signup and view all the answers

When is a rough sketch typically prepared?

During the initial walkthrough of the crime scene Signup and view all the answers

What distinguishes a site plan from a floor plan?

A site plan provides a bird's eye view specifically for outdoor crime scenes. Signup and view all the answers

Which method of measurement is best suited for outdoor crime scenes?

Triangulation Signup and view all the answers

What is included in the documentation block of a crime scene sketch?

Case number, offence type, and the sketcher's affiliation Signup and view all the answers

Which type of sketch combines both floor plan and elevation features?

Cross-sectional plan Signup and view all the answers

What is a significant benefit of using elevation plans?

They capture items of interest located in vertical planes. Signup and view all the answers

What should be done if there is uncertainty about taking a photo at a crime scene?

Take the photo anyway. Signup and view all the answers

Which of the following is a critical aspect of photography at a crime scene?

Every photograph must be logged in the photo log. Signup and view all the answers

What is the primary concern during a crime scene search?

Prioritizing evidence at risk of deterioration Signup and view all the answers

Which search method allows for specific zones to be prioritized?

Zone Method Signup and view all the answers

What is a major disadvantage of the Grid Method?

Time-consuming to conduct Signup and view all the answers

What is the first step in the vehicle search process?

Beginning with the exterior of the vehicle Signup and view all the answers

Which method involves searching from a critical point outward?

Spiral Method Signup and view all the answers

During documentation, which task is typically performed last?

Sketching Signup and view all the answers

Why is taking notes critically important during a crime scene investigation?

It provides a permanent record of the scene Signup and view all the answers

Which search method is least suitable for large crime scenes?

Wheel Method Signup and view all the answers

What is one of the primary reasons crime scene investigators prefer systematic searches?

To ensure all potential evidence is documented Signup and view all the answers

The Link Method is based on which principle?

Theories of probability and observation Signup and view all the answers

Which event must be documented during a crime scene investigation?

Notification and arrival information Signup and view all the answers

What should be avoided during the search to maintain evidence integrity?

Altering evidence to fit narrative Signup and view all the answers

Which method is particularly popular in forensic anthropology?

Strip Method Signup and view all the answers

What is the primary transmission route for mitochondrial DNA?

Maternal line Signup and view all the answers

Which of the following is true regarding presumptive tests for blood?

They can produce false positives. Signup and view all the answers

What is a key advantage of using Bluestar over luminol at a crime scene?

Non-toxic Signup and view all the answers

What is the primary role of confirmatory tests in forensic analysis?

To confirm positive results from presumptive tests Signup and view all the answers

Which presumptive test can show a color change indicating blood when combined with hydrogen peroxide?

Phenolphthalein (Kastle-Meyer) Signup and view all the answers

How can mitochondrial DNA impact criminal investigations?

It can identify the victim through relatives. Signup and view all the answers

What disadvantage do Hemastix tests have in forensic analysis?

Interferes with DNA samples Signup and view all the answers

What should NOT be done during the presumptive testing of blood at a crime scene?

Use a chemical directly on the stain Signup and view all the answers

Which property makes luminol sensitive in crime scene investigations?

Its reaction to iron in hemoglobin Signup and view all the answers

Which test is specifically designed to check for the presence of blood in urine?

Hemastix Signup and view all the answers

Study Notes

Week 1-LEC 1: Law and Science

Criminal justice systems use both law and science, each with distinct goals and methodologies
Law establishes frameworks for regulating behaviour and criminal proceedings
Scientific methods describe the natural world using hypotheses and evidence
Forensic science applies scientific principles to legal issues

Week 1-LEC 1: Definitions

Forensic science is derived from the Latin "forensis" meaning "public debate or discussion"
Forensic science is the application of science to legal matters
Scientific study of crime is hard to define as it relates to a broad range of disciplines.

Week 4-4A LEC: Arriving on Scene

Law enforcement response guidelines are critical for ensuring evidence integrity.
Initial responders prioritize preservation of life ahead of evidence collection.
Documentation of scene alterations is required

Scene Alteration

Scene alteration is not a problem if a reasonable explanation exists as jurisdiction for such actions
Examples of reasonable alterations are damage to gain entry and damage from suspect apprehension.

Roles of Responding Police Officer

First responder officer to arrive; duties include safety and preservation of life
Responsibile for maintaining scene security, preservation, and documentation
Responsible for transferring responsibility to the crime scene investigators and for giving a preliminary briefing to all the responding officers at the crime scene

Crime Scene Investigation: Documentation

Documentation is crucial for integrity of all evidence collection, as well as scene procedures and actions
Documentation should reflect time of entry and exit, reasons for entry, documentation of anything that is inconsistent with the evidence, and a thorough documentation of what was observed and witnessed
Documentation should be done as soon as possible, and all collected facts and materials should be recorded, even if seemingly insignificant

Scene Security & Preservation

Maintaining scene security is fundamental as it avoids contamination, changes to the scene, or loss of evidence.
Techniques include physical presence, lines, barricades, and other methods.
Documentation (e.g., log) records all who enter and exit the crime scene.

Week 7-7a: Types of Evidence: Definitions

Evidence is any documented information or matter used in legal proceedings for proving or disproving a fact or legal argument.
There are 3 main categories: testimonial, documentary, and real.

Real Evidence: Physical/Biological

Evidence can be either non-living (physical) or living (biological), and each may be classified in many ways.
Physical evidence (non-living), including fingerprints, trace evidence (e.g., fibers, paint, soil), or impression evidence (e.g. tool marks, tire impressions).
Biological Evidence (living), including DNA, body fluids (e.g., blood, saliva, semen), hair, and other biological traces.

Week 7-7B: DNA and Body Fluid Evidence: Introduction

Serology is the study of bodily fluids, including the analysis of blood, semen, and saliva.
DNA is a two-stranded molecule, a double helix composed of nucleotide chains.
Human body cells can be tested for nuclear or mitochondrial DNA.

DNA Types

Nuclear DNA is found in the cell nucleus; each person has unique DNA (except identical twins)
Mitochondrial DNA (mtDNA) found in cell mitochondria; maternally inherited
More useful for degraded samples but doesn't allow the individual to be determined with surety.

Presumptive and Confirmatory Tests for Blood

Presumptive tests are initial tests in identifying a substance (such as blood) as a possible blood stain, while Confirmatory tests are done in a lab to confirm the substance.

Crime Scene Preservation and Collection

Storage guidelines for body fluids, including moisture, temperature, contamination, and proper collection and packaging procedures.

Analyzing Body Fluids

Forensic scientists use tests for identifying trace evidence, such as chemical tests for blood, saliva, and semen.
Presumptive tests provide probable presence of a substance.
Confirmatory tests confirm the presumptive tests' results in an accredited laboratory.

Trace Evidence

Microscopic materials (e.g., fibers, pollen, paint, soil) commonly identified through techniques requiring a microscope
These provide forensic data for evidence investigation
Collection and preservation methods for trace evidence to prevent contamination, including packaging, labeling, and appropriate handling precautions.

Week 7-7b: Methods of Search

Techniques for Locating Evidence: Methods for systematically searching a crime scene, including strip, grid, zone, and spiral methods.

Impression Evidence

Footwear prints, tire tracks, and tool marks can reveal important information about the perpetrator.
Collection and preservation techniques for impression evidence, including use of photography, casting procedures, and other methods.

Week 8B-Week 11 Firearm and Toolmark Evidence: Review of Types of Evidence, Definitions

Firearm/toolmark analysis involves identifying the tool/firearm used in a crime.
Class characteristics: common feature(s) of the tool or weapon
Individual characteristics: unique feature(s) of the tool or weapon.

Crime Scene Documentation Methods

Detailed documentation of scene (e.g. sketches, photographs, notes) including location, time, who was involved, and actions taken in a sequential order. Evidence and its location (by coordinates, e.g) must be documented.

Presentation of Findings

Presentation of findings to the court is crucial to the legal process.

Ethics and Integrity

Ensuring that forensic work is ethical is critical and professional, following guidelines to avoid bias and mistakes.

Misconceptions

Critiques of forensic science, including the "CSI effect," which presents the subject in an unrealistic light.

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Description

Test your knowledge on the key principles and practices of crime scene investigation. This quiz covers topics such as chain of custody, crime scene management, and techniques used for evidence collection. Perfect for students and professionals in forensic science or criminal justice.