FS Fall Final Review

Ch 1 and 2 observations and CSI Forensic investigators recognize, document, collect evidence left at the scene of a crime. Factors that affect observational skills such as emotion, perception and recall,time of day, level of interest, number of people… DOCUMENT DOCUMENT DOCUMENT

How does your brain work?

Your brain… Filters (what is important, what you notice, your level of interest, who you are with, where you are….) Fills in gaps (D yo kno wht I mn?) Applies previous knowledge –connect with what you know so it makes sense

Scientist Galton Locard Landersteiner Bertillion

Direct vs Indirect Circumstantial

Class vs Individual Blood type-A B AB O Shoe or tire impression Hair Fingerprint DNA Bitemark Hair follicular tag

Physical Evidence

Trace

Who does what? Who secures the scene and separates witnesses? Who takes measurements and notes location of evidence? Who interviews the witnesses? Specialists?

First Find, then

NOTES-WHY?? Write brief, legible, abbreviated notes that others will be able to understand. Notes in INK Bound notebook Mistakes crossed out with single line Pages numbered consecutively Pages initialed

Why secure the scene?

Primary vs Secondary Crime scene

Crime Scene Team Police Officers (First Responders) Usually first at scene Secure Scene Crime-Scene Investigators Document crime scene in detail and collect evidence Recorders, sketch artists, photographers, evidence collectors Medical Examiners (Also known as coroners) May be present to determine the cause of death if a homicide or “possible” homicide occurred. Detectives Look for leads Interview witnesses Forensic Specialists Certain crime scenes may call for experts in certain areas to be on scene Example – entomologists, anthropologist, toxicologist, odontologist

Identify the regions of hair

What part of the hair is shown?

DNA?

Human or NON-human Cuticle?

Consistent? Dissimilar? Inconclusive?

Is Hair CLASS or INDIVIDUAL evidence?

Medulla

Locard Every contact leaves a trace Duration Intensity Materials used

Control?

Fingerprint Minutiae

Fingerprints 1. unique 2. unchanging 3. can be used to ID individuals arches, loops and whorls Principles of Fingerprints 1. unique 2. unchanging 3. can be used to ID individuals

Kinds of Crime Scene Prints Patent /Visible prints – bloody, muddy, dirty…. Plastic Prints – ridge impressions left on a soft material (putty, wax, soap or dust) Latent/invisible prints – Must be LIFTED Porous-ninhydrin, iodine Nonporous-powder

Identify each fingerprint pattern. ? A B Right Hand Left Hand C Right Hand E D Right Hand Left Hand 29

How can we use these?

What Can be learned from tire impressions? What type of impression is shown?

What can you learn from studying the gait (walking pattern)

Fire Classification Accidental Natural Intentional -Arson undetermined

COMMON MOTIVATIONS FOR ARSON $$$-insurance fraud, for profit Revenge, spite, jealousy Vandalism/malicious mischief Racial/religious hostility Crime concealment/diversionary tactics Psychiatric afflictions Vanity, hero fire

Glass as evidence By analyzing the fracture patterns: 1. what object hit the glass 2. from which direction the object came 3. sequence of events 4. composition of specialized glass

Why is Chain of Custody so important?

Questioned Documents Checks Passports Driver’s license Prescriptions Wills notes

Fraud vs Forgery?

Exemplars (Control)