THE INVESTIGATION PROCESS, EYEWITNESS TESTIMONIES, THE INNOCENCE PROJECT, AND CLASSIFYING EVIDENCE

Laboratories need … to run.

evidence

Evidence can be what … or … a case.

makes, breaks

What can evidence be used to do?

1. convict

2. exonerate

3. prove (guilty or not guilty)

What needs to happen for evidence to be examined in a lab?

recognization by the investigator and preservation

Who is at the crime scene?

1. police and district attorneys

2. crime scene investigators

3. medical examiners

4. detectives

5. specialists

chain of custody

the chronological documentation or paper trail that records the sequence of custody, control, transfer, analysis, and disposition of physical or electronic evidence

What are the steps that crime scene investigators follow?

1. Securing the Scene

2. Separating Witnesses

3. Scanning the Scene

4. Seeing the Scene

5. Sketching the Scene

6. Searching the Scene

7. Securing and Collecting Evidence

What is testimonial evidence?

includes oral and written statements given to police and testimonies in court

Despite eyewitness accounts being unreliable, police and investigators use them to produce … to help gain evidence.

leads

What can play a role in the accuracy of an eyewitness statement?

age, stress levels, and drug use

What is the cross race effect?

a phenomenon where people are better at recognizing faces of their own race rather than those of other races

What can influence memory?

other people, the time of day, and the view of the crime

Investigators must ask witnesses what type of questions?

open-ended

How long does it take for a witness to possibly remember the face of their perpetrator?

a minute or longer

What faces are more recognizable?

highly attractive or unattractive

What are facial composites?

sketches of criminals made by sketch artists working with investigators

What is FACES?

a software program that offers many options to recreate a person’s facial features

What is the purpose of the Innocence Project (innocenceproject.org)?

to reexamine post-conviction cases and exonerate those that are wrongfully convicted

Who are the founders of the Innocence Project?

Barry Scheck and Peter Neufeld (Est. 1992)

What percentage of cases revisited by the Innocence Project have led to exonerations?

87%

How many cases have been reviewed by the Innocence Project?

over 360

Securing the Scene

• Who? = the first official responder on scene

• What? = setting clear boundaries around a crime scene to protect evidence

• When? = immediately as the first responders arrive to the scene

• Why? = to protect evidence from destruction and to protect the public from danger

• How? = by using barriers and yellow caution tape

Separating Witnesses

• Who? = first responders, CSI, and detectives

• What? = keeping witnesses apart so they don’t contaminate stories

• When? = immediately after securing the scene and prioritizing medical safety

• Why? = to prevent blending stories together

• How? = officers taking individuals to separate locations to be interviewed

Scanning the Scene

• Who? = crime scene investigators, forensic technicians, and lead investigators

• What? = using 3D laser scanners and taking photos

• When? = right after securing the area and separating witnesses

• Why? = allows investigators to see evidence and plan a detailed search

• How? = doing a walk-through at the scene, placing temporary markings, and noting the layout

Seeing the Scene

• Who? = forensic photographers and investigators

• What? = taking photos of the overall scene

• When? = as soon as it’s safe

• Why? = so the courts can have photo evidence and measurements of objects at the scene

• How? = usage of a camera and baseline observations

Sketching the Scene

• Who? = a crime scene investigator, forensic artist, or specialist

• What? = the actual layout of the crime scene being documented

• When? = after photos are taken and before anything is moved or disturbed

• Why? = to create an accurate record of the crime scene layout and space

• How? = photography, notes, and active sketches

Searching the Scene

• Who? = forensic technicians and specialized detectives

• What? = scanning tracks, blood, hair, prints, etc.

• When? = after first responders handle the area, emergency needs, and walk-throughs

• Why? = helps uncover physical evidence

• How? = using systematic search patterns to document

Securing and Collecting Evidence

• Who? = CSI

• What? = evidence being collected and placed in proper containers

• When? = after evidence is photographed and added to crime scene sketches

• Why? = to ensure evidence is not contaminated

• How? = evidence being collected and stored appropriately to be transferred to a lab and courtroom

What is direct evidence?

includes firsthand observations (eyewitness accounts, police dashboards, video surveillance, voice recordings, signed ransom notes, and reports)

What is circumstantial evidence?

indirect evidence that can be used to imply a fact, not directly prove it (prints, DNA, fibers, and hair)

What is circumstantial physical evidence?

all prints, bullets, weapons, synthetic fibers, etc.

What is circumstantial biological evidence?

DNA, hair, natural fibers, etc.

What is class evidence?

evidence that narrows the case down to a specific group of people/items (shoe prints, blood types, loose hair, etc.)

What is individual evidence?

evidence that narrows the case down to one individual (DNA, loose hair, fingerprints, etc.)

Who was Dr. Edmond Locard?

the “father of forensics” who established the first forensics lab in Lyon, France in 1910

What is Locard’s Exchange Principle?

states that when you touch something, a cross-transfer of physical evidence can occur, the intensity of contact affecting the amount of exchange

What are examples of trace evidence?

skin cells from grabbing someone’s shirt or fingerprints from holding a weapon

What is forensic science?

using scientific knowledge and techniques to help solve a criminal investigation

What is the role of a forensic scientist?

to analyze evidence, to be an expert witness in court, and to explain test results

What is the most common type of evidence found at a crime scene?

circumstantial