TERM 1 FORENSICS NOTES

Eye piece

Aka the ocular lense

A place to view the specimen

Body Tube

Connects the Ocular Lens to the Objective Lenses and provides alignment to direct the light from the specimen into the viewer's eye.

Arm

allows user to hold the microscope securely

Coarse Adjustment Knob

Moves the stage up and down. Should never be used in high power.

Fine Adjustment

fine tunes the focus

used with all objective lens

Revolving Nosepiece

rotates to change between different objective lenses

Objective Lenses

3 or 4 different lenses with varying magnification ranging from 4X to 40X

High (40X)- longest, lens closet to the specimen

Low Power

This objective lens provides the lowest magnification, 4 x

Medium Power

This objective lens provides a medium magnification, or power, 10x

High Power

This objective lens provides the highest magnification, 40x

Stage

holds the slide and has a window that allows light to pass through the specimen

Stage Clips

these clips hold a slide in place on the stage for viewing

Diaphragm

turns to adjust the amount of light that passes through the specimen

Base

Supports the microscope

Light Source

shines through the specimen and to the lenses

Total Magnification

Eye piece: 10X times the eye piece 4X, 10X, 40X

Glassware safety:

never use broken glass

always wear safety goggles

never heat wet glassware

use heat resistant gloves

Fire Safety

safety goggles

never heat anything with closed container

never heat anything unless instructed to

know location of fire extinguisher

Heat Safety

Always use clamps, tongs, or heat resistant gloves to handle hot objects

Have a clean work area

Chemical Safety

Never smell directly- WAFT

Never mix chemicals unless instructed to do so

Never touch or taste chemicals unless instructed to do so

Keep all lids closed when chemicals are not in use

Dispose of chemicals as instructed by teacher

know location of eye wash and shower

Immediately rinse with water if any chemicals get on your skin or clothes

Eye and Face Safety

Must wear safety goggles

When heating a test tube or bottle, always point away from you and others

Sharp Instrument Safety

Handle sharp objects with care

Always cut materials away from you

Notify your teacher if your skin is cut

Electrical Safety

Do not plug more than two appliances in any one outlet

Never touch an electrical appliance/outlet with wet hands

Keep liquids away from appliances and outlets

Animal safety

do not cause pain or injury to an animal

do not perform inhumane stunts/actions with an animal specimen

Wash you hands thoroughly after handing animals or their cages

Beaker:

holds substances

can be used to measure

can be used to heat

Test Tube:

holds substances

Microscope:

magnifies objects too small to see with the naked eye

Latex gloves:

protect gloves

Forceps:

helps grab small objects

Thermometer:

measures temperature; mercury

Pipette:

transfers small amounts of liquid

Test Tube Rack:

holds test tubes

Safety goggles:

protects eyes

Magnifying glass:

magnifies objects

Petri Dish:

used to culture micro-organisms and cells

Microscope slide:

holds specimen while viewing under microscope

Cover slip:

protects specimen while viewing under the microscope

Probe:

used to move, seperate and pin specimens during dissection

Graduated cylinder:

measures liquids

Forensic investigators must rely on their ability to ______, ______, and ______ observations clearly.

observe, interpret, report

Examiners must be able to identify the evidence, record it, and determine its ___________.

significance

This is difficult, as human ____ is always a possibility

error

We are constantly gathering information about our __________

surrounding

5 senses

Touch, Taste, Smell, Hearing, and Sight

Our brain _____ this information from our senses

filters

Our brain can’t hold all of the information that is observed on a daily basis. Paying attention to detail takes _____ ______

conscious effort

Observations cannot be confused with _______

perceptions

Perceptions are made as a result of an _______ and can be ______

observation; faulty

Ex. If you get cold every time you go in the bank, then you may believe that all banks are cold

How does our brain take observations and process them

Information from our senses

What we pay attention to

Perception

Short-term memory

Long-term memory

Memory fades with ____ (long term memory.) If you don’t use it you'‘ll lose it

time

The brain contains 4 ______ (regions)

lobes

Frontal Lobe

associated with reasoning, planning, parts of speech, emotions, and problem solving- fully developed at 25

Parietal Lobe

associated with movement, orientation, recognition, perception of stimuli

Occipital Lobe

associated with visual processing; back of skull

Temporal Lobe

(auditory section) associated with perception, memory, and speech: either side of head

Forensic investigators are not the only people that rely on good observation skills to solve crimes. Many times, investigators must rely on the observation skills of the ___ ______ at a crime scene

eye witness

Testimonial evidence includes ____ or ______ statements given to police as well as testimony in court by people who witnessed an event

oral, written

Eyewitness accounts can be a useful tool in helping investigators with analyzing crime scenes, but are not viewed to be highly ______. In addition, eyewitness identifications (right or wrong) can have a big influence on the outcome of an investigation or trial

reliable

Though this topic is highly debatable, most states have accepted eyewitnesses accounts as ______ ______ and DO NOT allow a person(s) to be convicted based solely on eyewitness accounts

flawed science

However, police and investigators still use eyewitness accounts to produce ____ that then help to gain additional evidence that CAN be used to convict a suspect

leads

____ may play a role in the accuracy of an eyewitness’ statement or identification of a suspect

Age

a phenomenon in which people are better at recognizing faces of their own eace rather than those of other races

The Cross Race Effect (CRE)

The use of ____ can alter a person’s ability to recall the events of a crime even after they are no longer under the influence

drugs

A person’s ______ of an event can be influenced by other witnesses, investigators, and/or the media. Investigators use open-ended questioning and procedures to limit their influence on witness’ memory of an event or identification of a suspect.

memory

Investigators work with sketch artists and eyewitnesses to create _____ ________ or sketches of a person’s face. Today many police departments are using facial reconstruction software to help them with this task. The composite may be used internally to assist officers in identifying the suspect or used externally through local media (radio, TV, and newspaper) to solicit leads from citizens

facial composite

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

Faces

A crime that is extremely ______ may affect a witness’ recall of the event. For example, a witness confronted with a weapon tends to focus on the weapon rather than the perpetrator’s face.

traumatic

Someone who is able to ____ on a perpetrator’s face for a minute or longer will tend to have a more accurate memory than someone who saw the person for a few second

focus

_____ that are either highly attractive/unattractive or distinctive are more likely to be accurately recognized. Simple disguises can interfere with accurate eyewitnesses identification, but piercings and tattoos increases the likelihood of an accurate identification

Faces

The ____ of day in which the crime occurred and a person’s ___ of the scene may affect what a he/she is able to see and remember

time, view

Founders of the Innocence Project

Barry Scheck and Peter Neufeld

Purpose of the Innocence Project

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

-uses DNA evidence to provide conclusive proof of guilt/innocence.

-eyewitness accounts are not considered scientific evidence

Percentage of cases that have led to exonerations

87%

They have reviewed over ___ cases

360

Dr. Edmond Locard

-known as the father of forensics

-established the first forensics laboratory in Lyon France in 1910

- known for Locard’s Exchange principal

Locard’s Exchange Principal

states when a person comes into contact with an object (or another person), a cross-transfer (exchange) of physical evidence can occur

• the exchanged materials indicate that the two entities were in contact

• The intensity, duration, and nature of the entities in contact determine the extent of transfer

• Forensics is built upon this principle

• Evidence solves crimes

• This evidence bears a silent witness to the criminal act

Direct Evidence

includes firsthand observations

• eyewitness accounts

• police dashboard

• video surveilance

• Voice recordings

• SIGNED ransom notes

• Reports (toxicology, lab, etc.)

Circumstanitial Evidence

Indirect evidence that can be used to IMPLY a fact but not directly prove it

• Prints

• DNA

• Ballistic evidence

• Fibers

• Hair

-Physical or Biological

Circumstanitial Physical

• All prints

• Bullets

• Weapons

• Synthetic fibers-plastics

Circumstanitial Biological

comes from living things

• DNA

• Hair

• Natural Fibers-cotton

Class

narrows to a group of people/items

• shoe prints

• blood type

• hair(w/o follicle)

Individual

narrows to one individual

• DNA

• Hair (w follicle)

• Fingerprints

Just as car needs fuel to run, criminal laboratories also need ______ to run

evidence

Evidence can be what _____ or _____ a criminal case

makes, breaks

Evidence can be used to convict, exonerate or prove a defendant to be ___ guilty of an accused crime

not

Before evidence can be used, its presence must be _______ at the crime scene

recognized

Forensic Science begins at the _____ _____

crime scene

If the investigator cannot ______ evidence or cannot properly ______ it for laboratory examination, it is of no use

recognize, preserve

With proper training, police agencies and investigators can _____ competent performance at crime scenes

ensure

Who is at the crime scene?

Police or District Attorney (DA may be present to issue warrant)

Crime scene investigators (document scene in detail and collect evidence

Medical examiners (coroners, determine COD)

Detectives (look for leads, interview)

Specialists (toxicology, psycologists)

Chain of Custody

The chronological documentation or paper trail that records the sequence of custody, control, transfer, analysis, and disposition of physical evidence or electronic evidence is known as the…….

What are the steps that crime scene investigators follow

Securing the Scene

Separating witnesses

Scanning the Scene

Seeing the Scene

Sketching the Scene

Searching the Scene

Securing and Collecting Evidence

1. Securing the Scene (Who? What? When? Why? How?)

Who: The First Responder

What: Setting clear boundaries around a crime scene to protect evidence. secure if someone is injured or suspect is on site. Log who’s in & out

When: immediately as the responder arrives on the scene

Why: protect evidence from destruction/ contamination and to protect the public from danger

How: using physical barriers and controlling all accessible angles as well as using yellow caution tape

2. Separating Witnesses (Who? What? When? Why? How?)

Who: first responding officers & detectives or crime investigators handle separation. All individuals who witness the event, potential suspects, or bystanders are subject to separation

What: keeping witnesses physically apart so they cannot change stories. Conduct individual questioning

When: Immediately after securing the scene and prioritizing medical safety. Before any discussion can happen between witnesses

Why: avoid memory contamination, prevent conspiracy, and ensure accurate individual testimonies.

How: officers escort individuals to separate locations immediately. Investigators ask baseline questions

3. Scanning the Scene

Who: Crime scene investigators, forensic technicians, lead investigators officers.

What: 3D photos. Photos. Conducting a preliminary survey of the scene to identify evidence and potential paths of investigation.

When: right after securing the scene and separating witnesses.

Why: To develop an initial understanding of the crime and determine a strategy for evidence collection.

How: By carefully observing the scene, noting key locations, and taking initial photographs. Do a walkthrough.

4. Seeing the Scene (Who? What? When? Why? How?)

Who: Forensic investigators and photographers.

What: Take photos of the overall scene and close ups with items using evidence markers for size reference. Observing the crime scene for additional evidence and context.

When: After initial scanning and securing the scene.

Why: courts can have photo evidence and measurements of objects at the scene and overall area. To gather comprehensive information and identify overlooked evidence.

How: By conducting systematic searches and using appropriate forensic techniques. Use of camera and baseline observations of the scene.

5. Sketching the Scene (Who? What? When? Why? How?)

Who: Forensic artists and crime scene investigators.

What: Creating a visual representation of the crime scene, including the location of evidence, bodies, and other relevant details.

When: After photographing the scene and before evidence is processed.

Why: To provide a clear and accurate depiction of the scene for investigative purposes and court presentations.

How: By measuring distances, using scales, and incorporating photographic evidence to create detailed sketches.

6. Searching the Scene (Who? What? When? Why? How?)

Who: Crime scene investigators and forensic teams.

What: Systematic examination of the area to locate hidden or overlooked evidence.

When: After sketching the scene and once initial evidence is collected.

Why: To uncover additional information that may be pivotal to the investigation.

How: By employing various search methods, including grid, spiral, or quadrant techniques, and using tools like metal detectors or hand-held lights.

7. Securing and Collecting evidence (Who? What? When? Why? How?)

Who: Crime scene investigators and evidence technicians.

What: The process of gathering physical evidence from the crime scene, ensuring it is properly documented and preserved.

When: Following the search of the scene and before leaving the site.

Why: To maintain the integrity of the evidence for analysis and presentation in court.

How: By using appropriate collection techniques, labeling, and packaging methods to prevent contamination.

What is the 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