“Collins, I hate to start a Monday with a case like this!”

Forensic Science

Dan O’BrienPolson HighDepartmentof ForensicScience

ForensicScience

FORENSICSCIENCE

An Introduction

YOUR HOPES?

OUR HOPES?

Forensic Science

WHERE ARE WE GOING?

What is Forensic Science?

Forensic Science

A process based upon the SCIENTIFIC METHOD involving:

1 Analysis – studying an unknown item to determine its essential characteristics.

– Ex: Fingerprints recovered at a C.S.

What is Forensic Science?

Forensic Science

A process based upon the SCIENTIFIC METHOD involving:

2 Comparison – examining how the characteristics compare with characteristics of known items.

– Ex: Fingerprints on a recovered weapon

What is Forensic Science?

Forensic Science

A process based upon the SCIENTIFIC METHOD involving:

3 Evaluation – assessing the similarities and dissimilarities for identification purposes.

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What is Forensic Science?

Forensic Science

“FORENSIC”

– (Latin): “Forensis”:public, public discussion,

argument or debate.

What is Forensic Science?

Forensic Science

“FORENSIC”

– characteristic of, or suitable for, a court of law.

What is Forensic Science?

Forensic Science

“FORENSIC SCIENCE” The application of scientific principles to any criminal investigation.

What is Forensic Science?

Forensic Science

Also sometimes called “Criminalistics”.

A participant could be called either a “Forensic Scientist” or a “Criminalist”.

What is Criminalistics?

Forensic Science

“That profession and scientific discipline directed to the recognition, identification, individualization and evaluation of physical evidence by application of the natural sciences to law-science matters.”

Criminalistics

Forensic Science

“The science of Individualization”

- no two things in nature are EXACTLY the same.

- to demonstrate the uniqueness of an item of evidence.

EVIDENCE

Forensic Science

PERSONAL (eyewitness testimony)

PHYSICAL (fingerprints)

- very subjective & colored by personal attitudes & perceptions

- very objective & remains the same for each observer.

Characteristics

Forensic Science

All NEW tires from the same mold show CLASS CHARACTERISTICS

As a tire is used, it develops nicks and wear patterns that show INDIVIDUAL CHARACTERISTICS

Characteristics

Forensic Science

INDIVIDUAL CHARACTERISTICS allow a Criminalist to compare

the Questioned Evidence (a tire tread imprint at a CS)

to a Known Standard(a suspects tire)

INDIVIDUALIZATION

Forensic Science

Newcomb’s Rule: The probability of concurrence of all the separate events is equal to the continued product of the probabilities of all the separate events.”

- Dr. Simon Newcomb

INDIVIDUALIZATION

Forensic Science

A questioned document shows...a typewriter to have 5 individual characteristics: (84 keys total)

1/84 x 1/84 x 1/84 x 1/84 x 1/84

Total probability of uniqueness is1 out of 4.18 x 109 (~4 billion)

INDIVIDUALIZATION

Forensic Science

GOAL: to provide data that will show, in a court of law, that an item of evidence is in some way unique and may, in fact, be attributable to a unique individual & either help convict or exonerate that individual.

Name a FS “Field”? Forensic Pathology

Forensic Science

Forensic Entomology Forensic Anthropology Forensic Serology Forensic Toxicology Forensic Psychiatry

Name a FS “Field”? Forensic Odontology

Forensic Science

Forensic Photography Forensic Microscopy Forensic Chromatography Forensic Engineering Forensic Technologist

Name a FS “Field”? Firearms & Ballistics

Forensic Science

Fingerprints Chemistry Questioned Documents Impression Analysis Trace Evidence

Forensic Team

Detective / Investigator

Forensic Science

Crime Scene Technician

Lab Technician

Medical Examiner / Coroner

1st Responding Officer

State

Crime

Lab

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Missoula,Montana

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ForensicScienceAn Introduction