ADMJ 1100 Lecture Notes - Lecture 1: Alphonse Bertillon, Arnould Locard, Trace Evidence
17 May 2018
School
Department
Course
Professor
CSI
Chapter 1 Lecture Slides
Physical Evidence
Forensic Science: application of science to the law (notably within the context of the criminal
justice system
Criminalistics: branch of forensics, specialists trained in recording, identifying, and interpreting
physical evidence
Criminal Investigation: process of discovering, collecting, preparing, identifying, and presenting
evidence to determine what happened and who is responsible
- Reconstructive process that uses deductive reasoning (logical process in which a
conclusion follows from specific facts = reasoning backwards)
Alphonse Bertillon
- Founder of criminal identification
- Identification should be based on unchanging physical characteristics
- Anthropometry: method of identification (human body was measured in 11 places)
o Height, trunk, reach, left foot
Portrait Parle (speaking card): used for suspect identification with descriptions of the human
head and features
- Outgoth of Betillios sste
Edmond Locard
- Prior to the 19th century, witness testimony was favored over physical evidence
- Locad’s Echage Piciple: he thee is otat etee to ites, thee ill e
a ehage
o Criminal leaves trace evidence and takes away something from the crime scene
Types of Evidence
- Direct Evidence: evidence that proves a fact without the necessity of inference or a
presumption, and, when true, conclusively establishes that fact
o i.e. video, audio, and DNA
- Circumstantial Evidence: involves a series of facts that tends, through inference, to
prove a fact at issue
o Tends to incriminate a person (does not directly prove that the suspect
committed the crime)
o Set of circumstances from which an assumption can be made
▪ i.e. indirect evidence, suspect interviews, and testimonial evidence
- Testimonial Evidence: oral or written evidence given by a lay person or expert witness
o A lay witness is a witness to the crime who is interviewed by police and picks the
suspect out of a line-up
o An expert witness is someone who testifies on matters within their field of
expertise
▪ i.e. a doctor testifying about analysis of an x-ray
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o Can be direct or circumstantial evidence
- Physical Evidence: physical objects that are linked to the commission o a crime
o Must be recognized as potential evidence, collected in an appropriate manner,
and preserved properly
o Can be direct or circumstantial evidence
o Class Characteristics of Physical Evidence: physical qualities shared by a group of
like ites
▪ Class-only types of evidence are those which cannot be linked to a single
source
• May be shown to be like or consistent with a questioned source,
although not uniquely identifiable with that source
• Criminal cases based solely on class evidence are more difficult to
prove and require more work
• This evidence may be used to conclusively eliminate a suspected
source
• i.e. threads used in a common jacket, chemical structure of a
batch of heroin, manufacturer of a firearm, ABO typing of a blood
sample
o Individual Characteristics of Physical Evidence: physical qualities that are unique
to an individual evidence item
▪ Individualization: a pattern of class and individual characteristics
establishes the individuality of a specific object
▪ Process usually involves the comparison of the questioned item to a
known item
▪ i.e. a fingerprint, the striation marks on a fired bullet, the wear marks of a
used pair of shoes, the DNA code for a blood sample
Comparison Standards and Controls
- Questioned Item: an item with an unknown source that is to be compared with a known
source (usually collected from the crime scene, the victim, or the suspect)
- Known Source: evidence that originates from a known, acknowledged, or accounted for
source to be compared to the questioned evidence (gun recovered from suspect)
- Exemplar: type of known evidence collected from a known individual to be used for
comparison
The Comparison Process
When, Questioned item = Q and Known item = K
1. The class characteristics of Q do not agree with those of K
a. K is eliminated as the source of Q
2. The class characteristics of Q agree with those of K
a. If Q has only class characteristics, K may be the source of Q
3. The class characteristics of K and Q agree, but there is no agreement of individual
characteristics
a. K may not be the source of Q (inconsistent)
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4. The class characteristics of K and Q agree, and there is some agreement in individual
characteristics between Q and K
a. K may be the source of Q (consistent)
5. There is sufficient agreement in class and individual characteristics between Q and K to
establish that K is the source of Q
a. K is identified as the source of Q (individualization)
Evidence Collection Requirements
- Ethical: the crime scene investigator must be objective with regard to recognition,
documentation, and collection of physical evidence at any scene
- Scientific: prevent the contamination of the evidence, preserve the condition of the
evidence, collect adequate comparison standards, package in appropriate containers,
and store in appropriate conditions
- Legal Requirements:
o 4th Amendment Protections: the right of the people to be secure in their
persons, houses, papers, and effects, against unreasonable searches and seizures
(warrants with probable cause)
o If a crime occurs on private property, consent to search from another occupant
or a search warrant must be obtained
o Weeks v. US: evidence that is illegally seized by the police cannot be used in trial
(exclusionary rule)
o The Fruit of the Poisonous Tree Doctrine: evidence derived from an illegal
search or seizure cannot be used in trial
o Police do not need a warrant if there is consenting to search, exigent
iustaes, ojets ae i plai ie o i ope fields, ad ieitale
discovery
▪ Searches by consent are allowed as long as the person or property being
searched is freely and voluntarily waiving his or her 4th Amendment rights
• Consent can be implied if the owner or person in possession of an
item or place reports that a crime has been committed and
summons help
▪ A search incident to lawful arrest does not require a warrant (if a person
is under arrest, the police may search their person and any area
surrounding the person that is within reach
▪ Exigent circumstances: immediate and overriding need to search
• i.e. endanger the lives of others, suspect may be destroying
evidence, to stop a crime in progress or in hot pursuit, to perform
a protective sweep of the property
• Determined by degree of urgency, time to obtain a warrant, if
evidence is about to be removed or destroyed, danger at the site
▪ Plain View Doctrine: ready visibility of objects that might be seized as
evidence during a search by police in the absence of a search warrant
specifying the seizure of those objects
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Document Summary
Forensic science: application of science to the law (notably within the context of the criminal justice system. Criminalistics: branch of forensics, specialists trained in recording, identifying, and interpreting physical evidence. Criminal investigation: process of discovering, collecting, preparing, identifying, and presenting evidence to determine what happened and who is responsible. Reconstructive process that uses deductive reasoning (logical process in which a conclusion follows from specific facts = reasoning backwards) Anthropometry: method of identification (human body was measured in 11 places) Identification should be based on unchanging physical characteristics: height, trunk, reach, left foot. Portrait parle (speaking card): used for suspect identification with descriptions of the human head and features. Prior to the 19th century, witness testimony was favored over physical evidence. Loca(cid:396)d"s e(cid:454)cha(cid:374)ge p(cid:396)i(cid:374)ciple: (cid:862)(cid:449)he(cid:374) the(cid:396)e is (cid:272)o(cid:374)ta(cid:272)t (cid:271)et(cid:449)ee(cid:374) t(cid:449)o ite(cid:373)s, the(cid:396)e (cid:449)ill (cid:271)e a(cid:374) e(cid:454)(cid:272)ha(cid:374)ge(cid:863: criminal leaves trace evidence and takes away something from the crime scene.
