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

2. 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

3. 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.

4. 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.

5. 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

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

7. 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

8. 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

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

10. 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

11. 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

12. 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

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

14. 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

15. 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

16. 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

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

18. 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

19. 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

20. 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

21. 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

22. 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

23. Practice
Forensic Science: Fundamentals & Investigations, Chapter 1

25. 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: : :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

26. 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

27. 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

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

29. . . . . . . . . . . . . . . . . . . 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

30. 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.

31. 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

33. 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

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

35. 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

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

38. Chain of Custody

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

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

42. 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.

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

44. 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.

45. 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.

46. 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.