Exam 1 Review

Bertillon

Bertillon

first uses of scientific principles of identification (anthropometry)

known as the "father of criminal identification"

Locard

developed “Locard’s exchange principle.”

held that any time two items come into contact, a cross transfer of materials occurs (every contact leaves a trace)

Doyle

created detective Sherlock Holmes

Goddard

utilized the comparison microscope to further the field of firearms identification

CSI Effect OJ Simpson Case

first time DNA was used in high profile case

Berry Shack: DNA expert, attorney in case, created Innocence project

Crime labs

Who created them:

First: Los Angeles PD (created by August Vollmer)

Largest: FBI Crime Labs (created J. Edgar Hoover in 1932)

Laboratory Analyses

Physical Sciences Unit: examines trace evidence such as soil drugs, paint etc.

Biology Unit: performs DNA analysis, serology, and examinations of other living evidence such as botanical evidence.

Firearms unit: conducts examinations of firearms, bullets, and performs ballistic and gunshot residue (GSR) analysis.

Latent Fingerprint Unit: examines and compares fingerprint evidence. In some labs, this unit may be combined with biometrics to allow identification such as facial recognition.

Lab Analyses

Document Examination: processes handwriting and keyboarding analyses whose authorship or authenticity are in question.

Photography unit: conducts the processing and enhancement of still and moving video evidence.

Toxicology unit: checks for poisons in the body and also is used for intoxication analysis by drugs and alcohol.

Other units: include specialized services such as voiceprint analysis, polygraph, and crime scene processing units.

Non-lab Analyses

Forensic pathology: utilizes medical examiners and autopsies to attempt to determine the cause and manner of death.

Forensic entomology: studies insects at a crime scene, almost always a death scene, often to help determine a time of death.

Forensic Anthropology: uses specially trained anthropologist and are most often used to help identify decomposed or skeletonized remains.

Forensic Psychiatry: used in many different settings, included (but not limited to) criminal profiling, determinations of insanity and competency, and reliability of eyewitness evidence.

Forensic Engineering: applies physics and engineering principles to accident reconstruction, fire origin, and structural failure analysis.

PCAST Report

President’s Council of Advisors on Science and Technology

panels consisted of scientific experts; some were forensic scientists and other were experts in their fields.

focused on feature comparison

NAS Report

National Academy of Sciences

Came before the PCAST report

focused on Feature-Comparison methods used in specific disciplines, comparing them to DNA standards.

Nuclear DNA was the gold standard

The Rape Kit Backlog

Feature comparison

involved human being comparing features to see if they are identical (ex: fingerprints, ballistics)

Black box study

Knowledge is stored in brain of analysts

proficiency testing - used to test people in the lab

principles for securing the crime scene

(1) boundaries of crime scene must be secured with crime scene tape, ropes, or cones.

(2) secured area should include the area where the crime took place and the surrounding area where physical evidence may be located, including entry/exit points.

(3) post guards to restrict access to the crime scene.

(4) keep detailed log is kept of personnel movements in/out of the crime scene; includes personnel names and time of entry/exit.

(5) investigators should never smoke, eat, drink, or litter.

role of the lead investigator

establishes a center of observations and assigns tasks after initial walk-through

ICS

Incident Command system

• important concept: when everything is going on and there is a transfer of who’s in charge it needs to be known (ex – Uvalde shooting)

• A formal process by which command and control of scenes is accomplished; a joint command may be established between Law Enforcement, Fire/Rescue and EMS

search patterns

(1) Line/Strip Search Pattern: One or two investigators start at the boundary of the crime scene and search in straight lines across to the other side of the crime scene (**most common)

(2) Grid Search Pattern: Two or more investigators form a grid by searching in line patterns that overlap and are perpendicular to each other.

(3) Spiral Search Pattern: One investigator searches in a spiral path from the center of the crime scene to the boundary (outward) or from the boundary of the crime scene to the center (inward).

(4) Wheel/Ray Search Pattern: Several investigators search in straight lines from the center to the boundary (outward) or from the boundary to the center (inward).

(5) Quadrant/Zone Search Pattern: The crime scene is divided into smaller sections (zones); one or more investigators are assigned to search each zone.

crime scene notes format

Begin with:

(1) The identity of person who contacted the investigator (2) Time of contact and arrival at the crime scene (3) Preliminary case information (4) Personnel present on arrival and those being contacted

Contains:

(1) a personnel log (2) all observations made by the investigator, and the times.

Format:

(1) uniform layout, concurrently as the observations are made. (2) written in a bound notebook in blue or black ink.

**when processing crime scene notes (handwritten) they must be complete and turned over

Photography

usually use digital camera - cheaper and works better for evidence

Types:

(1) Long range - shows placement of evidence

(2) Mid-range - show layout of smaller/significant areas; includes center of scene

(3) Close-up - shows features; with and without scale

Proper use of video imagery

must include overview, medium-range, and close-up images

should include the entire scene / surrounding areas

should show potential paths of entry / exit and movement

process for measuring crime scene evidence and creating rough sketch

use measuring tape and total station (more common)

Creating rough sketch:

(1) define boundaries

(2) establish known points to measure the locations of objects / evidence

(3) Draw walls/boundaries first and record dimensions

(4) Measurement should be taken from fixed points to pieces of evidence first

Different stages of work flow

(1) Protect and render aid to the injured

(2) Secure the scene

(3) Set up a command and plan the scene activity

a. CS used in significant scenes b. Obtain additional resources if necessary c. Obtain consent to search or warrant if required d. Do a scene “walk through”

(4) Search the scene and identify evidence.

(5) Process the Scene

a. photography b. notes/reports c. sketches/diagrams d. finished sketch

The 3 ways of documenting a crime

Notes, Sketches Photography

physical evidence and common types

any object that can establish that a crime has or has not been committed or can link a crime and its victim or perpetrator.

common types: blood, semen, saliva, fibers, fingerprints, hair, tool marks

identification and comparison

identification: the process of determining a substance's physical or chemical identity.

comparison: the process of identifying whether two or more objects have a common origin.

reference sample (known standard)

physical evidence whose origin is known that can be compared to crime scene evidence (ex - blood or hair from a suspect).

substrate control

Surface material close to areas where physical evidence has been deposited.

Purpose of substrate: identify contamination

Want a negative and a positive; two positives = contamination

databases available for the storage of physical evidence for comparison

chain of custody

a list of all people who came into possession of an item of evidence.

class characteristics

something that would be common to more than one person (ex - hair color and blood type).

contamination

the transfer of extraneous matter between the collector and the evidence or between multiple pieces of evidence, producing tainted evidence that cannot be used in the subsequent investigation.

individual characteristics

properties of evidence that can be attributed to a particular source with an extremely high degree of certainty (ex - DNA).

personal protective equipment (PPE)

prevent contamination of scene and investigator

(1) respiratory protection (2) eye protection (3) chemical protective clothing

walk-through

the initial survey of the crime scene carried out by the lead investigator to gain an overview of the scene in order to formulate a plan for processing the scene.

Absorption

• Absorption occurs when a contaminant comes in contact with unprotected areas of the body.

• Though absorption can occur through contact with intact skin, the greatest risk is through mucous membranes like the nose, mouth, or eyes

• a particular risk is the eyes; contaminant can splash into the eyes, or a technician may touch their eyes with a gloved hand and introduce the contaminant into the eyes.

Ingestion

Ingestion includes the introduction of a contaminant into the mouth. For this reason eating, drinking, or smoking should only occur in the cold zone.

Inhalation

Inhalation occurs when a contaminant is inhaled through the respiratory system.

Injection

Injection occurs when the skin is pierced; is a risk when handling needles or sharp objects.

Presumptive and confirmatory testing

Presumptive testing

– normally color test – usually testing drugs – presume it is x

Confirmatory test

– send to lab (GCMS) – that is x for sure