x All rights Reserved South-Western / Cengage Learning © 2012, 2009 Forensic Science: Fundamentals & Investigations, Chapter 1

Chapter 1 Observation Skills By the end of this chapter you will be able to: Define observation and describe what changes occur in the brain Describe examples of factors influencing eyewitness accounts of events Compare the reliability of eyewitness testimony with what actually happened Relate observation skills to their use in forensic science Define forensic science Practice and improve your observation skills Forensic Science: Fundamentals & Investigations, Chapter 1

Chapter 2 Crime-Scene Investigation and Evidence Collection By the end of this chapter you will be able to: 2.1 Summarize Locard’s Principle of Exchange. 2.2 Identify four examples of trace evidence. 2.3 Distinguish between direct and circumstantial evidence. 2.4 Identify the types of professionals who might be present at a crime scene. 2.5 Summarize the seven steps (seven S’s) of a crime-scene investigation.

Chapter 2 Crime-Scene Investigation and Evidence Collection By the end of this chapter you will be able to: 2.6 Explain the importance of securing the crime scene. 2.7 Identify the methods by which a crime scene is documented. 2.8 Demonstrate proper technique in collecting and packaging trace evidence. 2.9 Explain what it means to map a crime scene. 2.10 Describe how evidence from a crime scene is analyzed.

Forensic Science The application of science to those criminal and civil laws that are enforced by police in a criminal justice system. Also called criminalistics

Forensic Scientist Analysis of evidence found at the crime scene Expert witness in court Performs scientific research Trains others in the field

Introduction The forensic examiner must be able to FIND—identify the evidence DOCUMENT—record the evidence INTERPRET—accurately determine the significance of the evidence Forensic Science: Fundamentals & Investigations, Chapter 1

Our brains can filter out information. What Is Observation? Our brains can filter out information. Point out some of the details in this photo. Forensic Science: Fundamentals & Investigations, Chapter 1

How information is processed in the brain What Is Observation? How information is processed in the brain Forensic Science: Fundamentals & Investigations, Chapter 1

Can you read this? O lny srmat poelpe can raed tihs. I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, t he olny iprmoatnt tihng is taht the frist and lsat ltteer be in the rgh it pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Amzanig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt! if you can raed tihs psas it on !!" Forensic Science: Fundamentals & Investigations, Chapter 1

What Is Observation? Our brains fill in gaps in our perception In order to make sense of what we perceive, our brains often enrich with detail what we see, taste, hear, smell, or feel After an event, we can believe things were part of the background even though they were not Forensic Science: Fundamentals & Investigations, Chapter 1

What Is Observation? Our brains apply previous knowledge to new situations What assumptions can you make about this scene? How might those assumptions be wrong? Forensic Science: Fundamentals & Investigations, Chapter 1

Test your Observation skills The Monkey Business Illusion Who Dunnit? Forensic Science: Fundamentals & Investigations, Chapter 1

Observations by Witnesses Observations are affected by: Their emotional states Whether they were alone, part of a group, or near others What type of and how much activity was going on around them Forensic Science: Fundamentals & Investigations, Chapter 1

Eyewitness Accounts Reports from individuals about crime scene events often vary. Observations depend on the level of interest, stress, concentration, and the amount and kind of distractions present.   Prejudices, personal beliefs, motives, and any lapse in time since the occurrence can also have an affect. Forensic Science: Fundamentals & Investigations, Chapter 1

The Innocence Project Barry C. Scheck and Peter J. Neufeld Benjamin N. Cardozo School of Law, Beginning in 1992, used DNA to examine post-conviction cases Faulty eyewitness identifications accounted for up to 87% of the wrongful convictions Forensic Science: Fundamentals & Investigations, Chapter 1

The Innocence Project Eyewitness Identification Forensic Science: Fundamentals & Investigations, Chapter 1

How to be a Good Observer Observe systematically Start at one part of a crime scene and run your eyes slowly over every space Look carefully at details of each piece of evidence Do not assume that later on you will be able to remember everything Forensic Science: Fundamentals & Investigations, Chapter 1

How to be a Good Observer Turn off filters Do not pay attention to only what you think is important.  On a crime scene you will not know what will turn out to be important.  Make a conscious effort to pay attention to all the details in your surroundings. Forensic Science: Fundamentals & Investigations, Chapter 1

How to be a Good Observer Collect Information first, interpret data later Look for patterns and make connections More information yields better interpretations Prejudices exist everywhere— eyewitness accounts your own thinking processes Forensic Science: Fundamentals & Investigations, Chapter 1

How to be a Good Observer Documentation, Documentation, Documentation Write down and photograph as much information as possible Be aware that memory is faulty Remember that our brains tend to fill in gaps in our perceptions Forensic Science: Fundamentals & Investigations, Chapter 1

Observations in Forensics Study situations Find clues in ordinary details Work backwards from the evidence to what led up to the crime Be patient Practice Forensic Science: Fundamentals & Investigations, Chapter 1

Practice Forensic Science: Fundamentals & Investigations, Chapter 1

Practice 1. What color coffee mug was in the picture? Blue Red Yellow 2. When was the deadline? Yesterday Today Tomorrow 3. What time was on the clock on the wall? 10:40 11:05 1:55 4. How many sticky notes were on the whiteboard? Four Six Eight 5. Which of the following was NOT in the picture? Stapler Trash Can Printer Forensic Science: Fundamentals & Investigations, Chapter 1

Practice 6. What was the name on the plaque on the desk? Bill Brian Carl 7. What color was the victim’s shirt? Black Blue Red 8. How many plants were in the picture? None One Two 9. What color was the marker in the desk drawer? Red Blue Green 10. Where was the book in the picture? On a box In the trash can Under the body Forensic Science: Fundamentals & Investigations, Chapter 1

. . . . . . . . . . . . . . Summary . . . . The environment and our natural sensory filters affect our ability to observe Eyewitness reports can be correct, faulty, or a little of both Acquiring good observation skills takes practice and training Forensic Science: Fundamentals & Investigations, Chapter 1

Practice The Eyewitness Test Forensic Science: Fundamentals & Investigations, Chapter 1

. . . . . . . . . . . . . . . . . . Summary Forensic scientists: Find and Document Evidence Evaluate and Interpret (Analyze evidence found at the crime scene) Provide expert testimony to courts Performs scientific research Trains others in the field Forensic Science: Fundamentals & Investigations, Chapter 1

Principle of Exchange Locard's Principle of Exchange When a person comes in contact with an object or another person, a cross-transfer of physical material can occur. The intensity, duration, and nature of the entities and contact determine the extent of the transfer.

Types of Evidence Direct evidence Circumstantial evidence First-hand observations Circumstantial evidence Indirect evidence that can be used to imply a fact but that does not prove it

Types of Evidence (continued) Class evidence Narrows an identity to a group of persons or things Individual evidence Narrows an identity to a single person or thing

The Crime-Scene Investigation Team Police officers Crime-scene investigators Medical examiners Detectives Specialists

The Seven S’S of Crime-Scene Investigation Securing the Scene Separating the Witnesses Scanning the Scene Seeing the Scene Sketching the Scene Searching for Evidence Securing and Collecting Evidence

Packaging Evidence The paper bindle is ideal packaging for small, dry, trace evidence.

Chain of Custody

Mapping the Outdoor Crime Scene (continued) Marking Evidence Collecting Limits

Mapping the Outdoor Crime Scene (continued) Measuring and Marking Evidence Positions

Crime-Scene Reconstruction Crime scene reconstruction involves: Forming a hypothesis of the sequence of events from before the crime was committed through its commission Comparing the evidence to witnesses statements Investigators need to maintain an open mind as they examine all possibilities.

Staged Crime Scenes Commonly staged types of crime scenes include: Arson Murder staged to look like a suicide Burglary

Summary Locard’s Principle of Exchange states that contacts between people and objects during a crime can result in a transfer of material. Evidence may be direct, as in eyewitness accounts, or circumstantial, which does not directly support a fact. Evidence may be physical or biological. Trace evidence is a small amount of physical or biological evidence.

Summary (continued) A crime-scene investigation team consists of police officers, detectives, crime-scene investigators, medical examiners, and specialists. A crime-scene investigation consists of recognizing, documenting, photographing, and collecting evidence from the crime scene. First-responding officers must identify the extent of a crime scene, including primary and secondary scenes when possible, secure the scene(s), and segregate witnesses.

Summary (continued) After examining the crime scene(s) and identifying evidence, the crime-scene investigators document the scene(s) with photographs and sketches. Crime scene(s) are sometimes precisely mapped to ensure that no evidence is overlooked. Evidence must be properly handled, collected, and labeled so that the chain of custody is maintained. Evidence is analyzed in a forensic laboratory, and the results are provided to detectives, who develop a possible crime-scene scenario.