“Collins, I hate to start a Monday with a case like this!” Forensic Science Dan O’Brien Polson High Department of Forensic Science

Forensic Science FORENSIC SCIENCE 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. =

 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 is 1 out of 4.18 x 10 9 (~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  1 st Responding Officer

State Crime Lab Missoula, Montana

- END - Forensic Science An Introduction