1. Bellringer: Answer the following in your notes
Police investigating an apparent suicide collect the following items at the scene:
a note purportedly written by the victim
a revolver bearing very faint fingerprints
traces of skin and blood from under the victims fingernails
What units of the crime laboratory will examine each piece of evidence?

2. CSI mistakes
CSI effect

3. Expert vs. Lay Witness

5. Functions of the Forensic Scientist
Forensic Scientists rely primarily on scientific knowledge. However, only half the job is performed in the laboratory while the other half takes place in the courtroom.
These functions fit into three categories:

6. 1. Analyzing of Physical Evidence
Physical evidence is less likely to be compromised or tainted by human emotions than eyewitness accounts from victims or witnesses
the analysis of physical evidence involves adherence to:
strict guidelines
systematic collection
organization and analysis of information
OF INFORMATION (THE SCIENTIFIC METHOD)
an understanding of admissibility of evidence is important
Frye, Daubert, Kumho, Coppolino

7. 2. Providing Expert Testimony
Forensic Scientist are called on to evaluate evidence when the court lacks the expertise to do so
Must establish competency by citing educational degrees, number of years of occupational experience membership in professional societies, special courses taken and any professional articles or books published.
Cross-examination may reveal weaknesses in background and knowledge
Demeanor and ability to explain scientific data clearly and logically to a judge and jury of non-scientists
Must be an advocate of truth and not take a side

8. 3. Providing Training
Evidence must be properly recognized, collected and preserved if it is to have value.
Many, but not all crime laboratories keep trained “evidence technicians”.
Sometimes a patrol officer or detective collects the evidence.
All officers engaged in fieldwork must be familiar with evidence collection.
These people are trained by laboratory staff through extensive personal contact, lectures, laboratory tours and/or dissemination of manuals.

9. Witnesses vs. Physical Evidence
Most witnesses do not intentionally lie on the witness stand
Human observation is limited by memory, suggestion, and interpretation
Memories can be confused or altered, but physical evidence stays the same
bunny Effect video

10. List a situation in which a warrantless search may be justified.
What is the first critical step of crime-scene investigation? Why is this step so important?
List a situation in which a warrantless search may be justified.
emergency circumstances
prevent immediate loss or destruction of evidence
search of a person and property within the immediate control of the person provided it is made incident two a lawful arrest
consent by parties involved

11. Forensic science begins at the crime scene;
It is imperative that physical evidence be recognized and properly preserved.

12. Securing and Isolating
The first officer arriving at the scene must:
preserve and protect as much as possible
Priority given to those needing medical assistance and to arresting the perpetrator.
Once the scene has been secured, the lead investigator determines the boundaries of the scene and establishes the perpetrators path of entry and exit.

13. Securing Crime scene Properly secured and protected first
thorough search to be sure there are no suspects or physical danger
safety PPE (personal protective equipment)
Need to protect yourself: head, eyes, lungs, hands, feet, and occasionally your entire body
Gloves
rubber booties for your feet
Goggles or a face shield
Respiratory filter to protect lungs

14. Recording the scene Notes, sketching and photography are used.
These will aid the investigation and be presented at trials.
It is becoming more common to use videotape as well.

15. Photography should include:
photograph the shoes of everyone at the scene
Overview of surrounding area
Points of exit and entry
If indoors, each wall area should be shown
If there is a body, photos should show its position, injuries and any weapons near by
The surface beneath the body
All items of physical evidence including close-ups
A ruler may be inserted near objects whose size may be of significance.
Panoramic views can be produced by pasting together images.
**If any items are moved, added or have changed position photograph may not be admissible as evidence**.

17. Sketching Sketching is done after the photographs are taken.
A rough sketch is done first
Objects are located by distance measurements from two fixed points.
Evidence is given letter designations
A legend is included below the sketch
A compass designating north is shown
A finished sketch contains all of the information in the rough sketch. It is drawn with presentation in mind. Sometimes CAD is used

18. Rough Sketch

19. Finished Sketch

20. Notes
Note taking is a constant activity throughout the processing of the crime scene
Notes should include:
A detailed description of the scene
The location of items of physical evidence recovered
The time the physical evidence was discovered, by whom, how and by whom it was packaged and marked.
Other noteworthy sights, sounds, smells, etc.
This record may be the only source of information for refreshing one’s memory months, perhaps years, after a crime has been processed.

21. Conducting a search Must be thorough and systematic
Overlooked evidence can lead to accusations of a cover-up attempt
How one proceeds depends on the locale and size but must include all probable points of entry and exit
What to search for is determined by the type of crime, for example in a homicide the focus will be on a search for the weapon; a burglary: tool marks at the point of entry
In most cases a search for latent fingerprints is required
Careful vehicle searches are also done

22. Crime scene search patterns

23. Locard’s Exchange Principle
The value of trace (or contact) forensic evidence was first recognized by Edmund Locard in 1910.
He was the director of the very first crime laboratory in existence, located in Lyon, France.
"Every Contact Leaves a Trace"
The Locard’s Exchange Principle:
"with contact between two items, there will be an exchange."
For example, burglars will leave traces of their presence behind and will also take traces with them. They may leave hairs from their body or fibers from their clothing behind and they may take carpet fibers away with them.
Source:

24. Physical evidence How does the textbook define physical evidence?
Physical evidence is any object that can establish that a crime has been committed or can link a crime and it's victim or a crime and it's perpetrator.
Forensic science starts at the crime scene where evidence is recognized and properly preserved.

25. Steps in evidence collection
Photography (
Sketches
Conduct a systematic search for evidence
Collect physical evidence
Maintain the chain of custody
Obtain standard reference samples
Submit evidence to the laboratory

26. Chain of Custody
EVERY person who has come into contact with the evidence
handled
examined
Acts as a “paper trail”
Failure to do so:
lead to questions regarding the authenticity and integrity of the evidence and the examinations
When evidence is is analyzed there must be a new seal made

30. Procedures for collecting evidence
Identify the evidence
(is it evidence, could it contain evidence?)
Decide which type of packaging would be the most appropriate
(plastic pill bottle, manila envelope, paper bag, a sealed container?)
Record where evidence was found
(living room, northeast corner of park, etc.)
Label the evidence
(victim’s shirt, hat)
Date and intial
(you will keep a record of when you collected the evidence and that you collected)

31. Tag the evidence for identification
Seal the evidence
(put tape on it to make sure no one else has opened/compromised the sample)
Fill out an evidence submission form
Maintain records on chain of custody
Every person that handles the evidence needs to log it.

32. Types of physical evidence
Paint
Glass
Explosives
Ballistics
Dust & Dirt
Impression evidence
Fracture matches
Wounds
Questioned documents
Insects
DNA Skeletal remains
Body fluids
Hairs & Fibers