The Jon Benet Ramsey Case Catalyst: What were the issues with the original investigation? What went wrong?

VIDEO What new evidence came into play in the case? How does this new Touch DNA technology work? Why is gathering as much evidence as possible important?

Crime Scene Investigation Do you think the Ramseys should have been exonerated? Why or why not?

Forensic Science: Fundamentals & Investigations, Chapter 2 4 Chapter 2 Crime Scene Investigation and Evidence Collection GATTACA clip

Forensic Science: Fundamentals & Investigations, Chapter 2 5 Chapter 2 Crime Scene Investigation and Evidence Collection By the end of this chapter you will be able to: summarize Locard’s exchange principle identify four examples of trace evidence distinguish between direct and circumstantial evidence identify the type of professionals who are present at a crime scene summarize the three steps of a crime scene investigation explain the importance of securing the crime scene identify the methods by which a crime scene is documented demonstrate proper technique in collecting and packaging trace evidence describe how evidence from a crime scene is analyzed All Rights Reserved South-Western / Cengage Learning © 2009

Forensic Science: Fundamentals & Investigations, Chapter 2 6 Vocabulary Crime scene investigation: recognize, document, and collect evidence at crime scene. Trace Evidence: small but measurable amts. Of phys./bio. crime scene Direct Evidence: firsthand obs. / video camera accounts of crime Circumstantial Evidence: indirect evidence that implies fact (but doesn’t prove it)

Forensic Science: Fundamentals & Investigations, Chapter 2 7 Principle of Exchange Dr. Edmond Locard, director of the world’s first forensic lab (1910, Lyon, France), established the idea of the exchange principle; namely that: 1. When a person comes in contact with an object or another person, a cross-transfer of physical material can occur. 2. Study of the material can determine the nature and duration of the transfer.

Forensic Science: Fundamentals & Investigations, Chapter 2 8 Types of Evidence Statements of a witness in court would be direct evidence. Indirect or circumstantial evidence, such as a fingerprint (physical evidence) or blood or hairs (biological evidence), would imply something, and is called trace evidence.

Forensic Science: Fundamentals & Investigations, Chapter 2 9 Types of Evidence ClassIndividual Identifies group of person/things Identifies specific person/thing

Forensic Science: Fundamentals & Investigations, Chapter 2 10 Types of Evidence ClassIndividual Identifies group of person/things Identifies specific person/thing e.g. Blood Typee.g. fingerprint

Forensic Science: Fundamentals & Investigations, Chapter 2 11 Types of Evidence Evidence taken from a crime scene. Direct or circumstantial evidence? Physical or biological evidence? Class or individual evidence? Explain why this would be or would not be trace evidence.

Forensic Science: Fundamentals & Investigations, Chapter 2 12 The Crime Scene Investigation Team Who is at the crime scene? Police and possibly a district attorney. Crime scene investigators. Medical examiners. Detectives. Specialists.

Types of Evidence bsapp.com

Documents Hand written Hand written Type or Printed Type or Printed Authenticity? Authenticity? bsapp.com

Glass How broken? How broken? Link a suspect to a crime scene Link a suspect to a crime scene Fingerprints Fingerprints Blood Blood bsapp.com

Soils, Minerals, Wood, and Other Vegetative Matter. Location Location Link suspect Link suspect Trace Evidence Trace Evidence bsapp.com

Fingerprints Mainstay of Forensics Mainstay of Forensics Who is on file? Who is on file? bsapp.com

Hair What type? What type? How removed? How removed? Match to a person Match to a person DNA DNA bsapp.com

Fibers Link suspect to a location or victim Link suspect to a location or victim Origin? Origin? bsapp.com

Firearms and Ammunition Circumstances of discharge Circumstances of discharge Link to suspect Link to suspect Link to weapon Link to weapon Link to victim Link to victim bsapp.com

Powder Residue Evidence of shooting Evidence of shooting Circumstances of shooting Circumstances of shooting Type of weapon Type of weapon bsapp.com

Explosives & Propellants Link to suspect or victim Link to suspect or victim Origin Origin bsapp.com

Tool Marks Match tool to scares Match tool to scares bsapp.com

Impressions

Drugs Type of Drug? Type of Drug? Strength? Strength? Origin? Origin? Legal? Legal? bsapp.com

Paint Origin Origin Match Match bsapp.com

Blood, Semen, Saliva, Organs, & other Physiological Fluids Origin Origin DNA DNA Condition Condition bsapp.com

Forensic Science: Fundamentals & Investigations, Chapter Summary Summary Locard’s exchange principle: contact between people and objects can transfer material that can determine the nature and duration of the transfer. Evidence can be direct, indirect (circumstantial), physical, biological, class, or individual. A crime scene investigation team consists of police, detectives, crime scene investigators, medical investigators, and specialists. Numerous types of evidence depending on the crime!

Forensic Science: Fundamentals & Investigations, Chapter Reminders Reminders Read pp & make a mnemonic device to remember the 7 S’s.