Intro to Forensics 1-3

NTSC 1115-002 Introduction to Forensics Final Study Guide

Day 1: Intro to Forensics

What is the definition of Forensic Science? Forensic Science is the application of science to the criminal and civil laws that are enforced by police agencies in a criminal justice system.

What / who are Crime Scene Specialist? A Crime Scene Specialist is a person who attends crime scenes to document, preserve the scene, collect and preserve evidence in cases which could range from homicides, sexual assaults. Break and enters, animal cruelty, child endangerment to provincial acts. They range from Fingerprints, Footwear, CBRNE, Forensic Entomology, Blood Pattern Analysis)

What are Lab Specialists? A Lab Specialist receives and processes the evidence gathers at scenes, analyzes the evidence and produces findings. They range from Trace evidence (Hair/ GSR/ Paint/ Substrate Composition), Biological (Serology and DNA), Toxicology, Pathology and Firearms/ Toolmarks

HISTORY:

Sir Francis Galton (1822-1911) – First definitive study of fingerprints and developed a methodology of classifying them for filing which consists of LOOPS, WHORLS, ARCH

Hans Gross (1947 – 1915) – First to describe the application of scientific disciplines to the field of criminal investigations. Detailed assistance of fields from microscopy, chemistry, physics, minerology, zoology, botany, fingerprinting and anthropometry.

Alphonse Bertillon (1853 – 1914) – French police officer who created biometrics measurements as a form of identification, Anthropometry.

Edmond Locard (1877-1966) introduced the scientific method in criminal investigations. Invented Locard’s principle of exchange which means when a person comes into contact with an object or person, a cross transfer of materials occur.

Mathieu Orfila (1787-1853) the first to publish on the detection of poisons and their effects on animals which would led to Forensic Toxicology.

Leone Lattes (1887 – 1954) discovered blood can be grouped into different categories such as A. B, AB and O.

Calvin Goddard (1891 – 1955) First to determine whether a particular gun fired a bullet based on a comparison from a test fired bullet from the same firearm. First to invent the comparison microscope for firearm examiners.

Scenario presented in class: Deductive reasoning or Inductive reasoning? Deductive reasoning is a logical approach from general ideas to specific conclusions versus Inductive reasoning is drawing conclusions from specific to general.

Critical Thinking: A process for analyzing evidence to gather conclusions about the facts of a crime.  

CATEGORIES OF EVIDENCE: 

Testimonial Evidence: Witness, Victim, Accused, Digital (Dispatch recording, cell phone recordings/ Interviews, Police Body Worn Cameras)

Physical Evidence: (Car, Keys, CCTV, Biological, fingerprint, other objects found, footwear) Anything of a physical nature that could be produced as evidence

Document Evidence: Receipts, Written Statements, Notes, online/ digital) 

CRIME SCENES:

How to secure, record and search a crime scene?

Security continuity or security

Notes, measurements, photographs and/or SCANNERS? 

What is the value of photographs at a scene? 

To document the crime scene as found when specialist attend the scene. This properly documents how the scene presented at the time of arrival and processing. Keep in mind other external factors that could possibly change the scene prior and after the scene.

Contamination: 

EMS, Police and Fire initial interaction

Weather, Victim, Witnesses/ Accused/ Other investigators

What is Chain of Continuity/ Custody? 

A list of all people who came into possession of an item of evidence. Why is this important? To demonstrate preservation of the evidence, any changes to the evidence (such as sampling, processing or dying for contrast) and whom was responsible for the evidence at any given time.

Day 2: Physical Evidence and the CSI Effect

Drugs:

These are measured when seized, a sample will be sent off to Health Canada to confirm the type and derivatives (cutting agents), also can be sent for toxicology

Explosives:

Any device containing an explosive charge, catalyst or timers can be analyzed. This lends to types of detonators and types of explosive material

Documents:

Although handwriting samples is not an exact science, types of paper, ink can be analyzed

Blood, Semen, Salvia:

Any suspected biological samples will be tested first to confirm serology then second DNA profiles and the quality of the sampling) This may include sampling from other physical objects.

Glass:

Glass Particles or fragments can be transferred to a person or object. Examination of bullet holes are quite common to determine which bullet hole was made first to last based on sequencing.

Hair:

Any Animal or human hair present that can be present that possibly could link a person to a crime

Fingerprints:

For the majority of scenes, prints are latent by nature. Through development techniques

can be photographs and documented.

Firearms and Ammunition:

Any firearm, intact or discharged ammunition or cartridges, suspected being involved in a criminal case.

Impressions:

Tire marks, footwear impressions, depressions in soil/ snow and other forms of track including glove markings.

Organs and Physiological Fluids:

Body organs and fluids are submitted for toxicology to detect the

possible existence of drugs/ poisons.

Paint:

Any paint, liquir or dried may have been transferred from the surface of one object to another the commission of a crime. Also can be in relation to vehicle collisions such as hit and runs.

Petroluem Products:

Any petroleum products removed from a suspect or recovered from a crime scene.

The most common are gasoline residue from a scene or arsons, grease/oil fires whose presence may suggest involvement in a crime.

Plastic Bags:

Disposible bags such as garbage bags may be evidentials in cases. Examinations are

conducted on associate bags with a similar bag in possession of suspect.

Plastic/ Rubber/ Other Polymers:

Remnants of manufactured materials recovered at a scene may be linked to objects recovered in possession of suspects.

Powder Residue:

Any item suspected of containing firearm discharge

Serial Numbers:

Includes all stolen property such as bikes, firearms that may be submitted for

restoration of the identification numbers

Soil and Minerals: All items containing soil or minerals that could link a person or object to a particular

location.

Toolmarks: This includes any object suspected of containing an impression of another object such as a common screwdriver or crowbar (this would also include paint transfers from the object)

Vehicle Lights: Examination of vehicle headlights and taillights is normally conducted to determine whether it was on or off at the time of impact. Physical matching of broken lights can be examined.

Wood and other vegetative matter: Any fragments of wood, sawdust, shavings, vegetative matter on clothing may provide linkage to a suspect.

Innocent Mechanism versus Evidentiary Value:

Innocent mechanism is described as evidence collected at a scene that can be corroborated by either natural course of events or accidentally introduced by happenstance.

Evidentiary Value is described as evidence, through deductive reasoning, which is collected at a scene that was either left by witnesses, victims or suspects which may have important value to the crime scene and investigation.

Expert Witnesses: A person who is permitted to testify at a trial because of special knowledge or proficiency in a particular field that is relevant to the case. In Canadian law, it is described as the evidence provided is relevant and its probative value is not outweighed by its prejudicial effect. The evidence must be necessary because it is outside the knowledge of the trier of fact (judge/jury). The evidence can only come from a properly qualified expert and must be scientifically acceptable. The expert witness is the only witness that can render an opinion on the stand. 

CSI Effect:

Ever since the television show CSI came out in the 2000’s, society’s viewpoint has taken a shift to viewing crime scene shows in higher regard than they should be for a fictional show. This has lead to higher rates of acquittal when forensic evidence is not present, making it more different for prosecutors to win convictions or higher rates of conviction when forensic evidence is present. The phenomenon has forced trial courts to address the evidentiary, procedural and constitutional issues raised by counsel.

TYPES OF BIAS

Cognitive Bias is specific type of bias that describes how an individual’s beliefs,

motives and situational context can affect the way in which criminal evidence is

collected and evaluated.

Confirmation Bias which is described how an individual’s personal motives can affect

that way in which criminal evidence is collected and evaluated.

Contextual Bias which describes how an individual’s consideration and judgement can

be influenced by background information.