Forensic Science: Fundamentals & Investigations, Chapter 2 1 What Makes a Good Observer? 1.Describe how I moved the first 3 objects in detail. 2.How many steps did I take to get from the desk to the back counter? 3.What color were my shoes 4.What was in my left hand as I walked from the back of the room to the front? 5.How was my hair when you first walked into the room? 6.What is missing from the back of the room? 7.What was the pattern of the eraser blocks on my desk at the start? 8.What was the pattern of the eraser blocks on my desk now (look up)? 9.What are the 4 ways to be a good observer?

Forensic Science: Fundamentals & Investigations, Chapter 2 2 Objectives: Chapter 2 Crime Scene Investigation and Evidence Collection Objectives: 1. Summarize Locard’s exchange principle 2. Identify four examples of trace evidence 3. Distinguish between direct and circumstantial evidence 4. Identify the methods by which a crime scene is documented

Forensic Science: Fundamentals & Investigations, Chapter 2 3 Principle of Exchange Established by Dr. Edmond Locard,  When a person comes in contact with an object or another person, a cross- transfer of physical material can occur  Study of the material can determine the nature and duration of the transfer

Forensic Science: Fundamentals & Investigations, Chapter 2 4 What could be Transferred? 1. Hair (eyelash) 2. Saliva 3. Skin 4. Blood 5. Fibers 6. Fluids 7. Nails 8. Tooth 9. Jewelry 10. Makeup 11. Scent 12. MANY MORE

Forensic Science: Fundamentals & Investigations, Chapter 2 5 Types of Evidence Direct evidence Testimony by a witness about what that witness saw, heard, or did

Forensic Science: Fundamentals & Investigations, Chapter 2 6 Types of Evidence Circumstantial evidence also called Indirect also called Indirect trace evidence trace evidence Physical evidence e.g., fingerprints e.g., fingerprints Biological evidence e.g., blood or hairs e.g., blood or hairs

Forensic Science: Fundamentals & Investigations, Chapter 2 7 Types of Evidence Explain why this would be or would not be trace evidence

Forensic Science: Fundamentals & Investigations, Chapter 2 8 The Crime Scene Investigation Team Who is at the crime scene? o Police and o District attorney (possibly) o Crime scene investigators o Medical examiners o Detectives o Specialists

Forensic Science: Fundamentals & Investigations, Chapter 2 9 The Seven S’s of Crime Scene Investigation 1. Secure the scene 2. Separate the witnesses 3. Scan the scene 4. Seeing the scene 5. Sketch the scene 6. Search for evidence 7. Secure the collected evidence

Forensic Science: Fundamentals & Investigations, Chapter Securing the Scene police o First Responder- police Is it safe? Preserve any evidence (prevent transfer, loss or contamination)

Forensic Science: Fundamentals & Investigations, Chapter Separating the Witnesses o DO NOT TALK TO EACHOTHER o Asked questions about the crime Who called it in Who did you see What did you see Can you identify persons Where were you

Forensic Science: Fundamentals & Investigations, Chapter 2 12 #3- Scanning the Scene o Where do you take pictures from? o Primary Vs Secondary Crime Scene Primary (Robbery at bank) Secondary (Suspect’s house)

Forensic Science: Fundamentals & Investigations, Chapter Seeing the Scene o All photos taken (with and without rulers) o Triangulation of stationary objects included in photos Various angles and distances Close ups

Forensic Science: Fundamentals & Investigations, Chapter Sketching the Scene o Note all positions, landmarks, doorways, windows, trees (outdoors) o Note all objects (placement is key)

Forensic Science: Fundamentals & Investigations, Chapter Searching for Evidence o Walk the grid o Vacuums, Lights, Forceps

Forensic Science: Fundamentals & Investigations, Chapter Securing and Collecting Evidence o Proper Packaging, sealing, labels Liquids/Arson  airtight & unbreakable container Biological  breathable so it can dry (prevent mold) o Paper Bindles o Chain of Custody Who did what and when

Forensic Science: Fundamentals & Investigations, Chapter 2 17 Closure o Tomorrow’s Crime Scene Clothing Observation

Forensic Science: Fundamentals & Investigations, Chapter 2 18 Packaging the evidence 1. Crease a clean paper and place evidence in the X position 2. Fold in the left and right sides, and then fold in the top and bottom 3. Put the bindle into a plastic or paper evidence bag affixing a seal over the opening 4. Write your name on the seal

Forensic Science: Fundamentals & Investigations, Chapter 2 19 Evidence ID Forms

Forensic Science: Fundamentals & Investigations, Chapter 2 20 Chain of Custody Maintaining a chain of custody log is essential to present credible evidence in court

Forensic Science: Fundamentals & Investigations, Chapter 2 21 Chain of Custody (cont’d.) 1. Bag the evidence Add identification Seal it Sign it across the sealed edge 2. Sign over to a lab technician Open bag on non-sealed edge 3. Return items to the evidence bag Seal evidence bag in another bag Sign the evidence log

Forensic Science: Fundamentals & Investigations, Chapter 2 22 Analyze the Evidence o Facts result from collected evidence processed by the forensic lab o Lead detective aims to see how facts fit into the crime scenario

Forensic Science: Fundamentals & Investigations, Chapter 2 23 Analyze the Evidence Lab results can: o Show reliability of witness accounts o Establish the identity of suspects or victims o Show suspects to be innocent or link them with a scene or victim

Forensic Science: Fundamentals & Investigations, Chapter 2 24 Crime Scene Reconstruction Crime scene reconstruction involves: o Forming a hypothesis of the sequence of events o From before the crime was committed through its commission

Forensic Science: Fundamentals & Investigations, Chapter 2 25 Staged Crime Scenes When lab results don’t match up with the testimony of witnesses Common examples: o Staging a fire—to cover bankruptcy o Staging a suicide—to cover a murder o Staging a burglary—to collect insurance money

Forensic Science: Fundamentals & Investigations, Chapter 2 26 Staged Crime Scenes Was the crime scene staged? Consider: o Does the type of wound match the weapon? o Could the wound be easily self-inflicted? o What were the mood and actions of the victim before the event? o What were the mood and actions of the suspect before the event?

Forensic Science: Fundamentals & Investigations, Chapter Summary Summary.... o Locard’s exchange principle: Contact between people and objects can transfer material that can determine the nature and duration of the transfer o Evidence can be direct or indirect Physical or biological traces o A crime scene investigation team consists of police, detectives, crime scene investigators, medical investigators, and specialists.

Forensic Science: Fundamentals & Investigations, Chapter Summary Summary o Investigations consist of recognizing, documenting, and collecting evidence. o First responding officers identify the extent of the crime scene, secure it, and segregate witnesses. o Crime scene investigators document the crime scene. o Evidence is collected, packaged, and labeled. o The evidence is analyzed and interpreted to fit the crime scenario.