Forensic Analysis of Metals, Paint, Soil, and Blood

Trace Elements

Elements present in concentrations less than 1%.

Forensic Paint Examination

Analyzes paint to link objects to crime scenes.

Composition of Paint

Paint consists of pigments, additives, and binders.

Electrocoat

Layer preventing rust on automobiles.

Primer

First layer, minimizes color with high pigment.

Base Coat

Layer providing the finished color of paint.

Clear Coat

Final layer for gloss and durability.

Microscopic Analysis

Used to examine layers of paint.

Soil Forensic Analysis

Links soil samples to crime scenes.

Soil Collection Radius

Samples collected within 100-foot radius.

Soil Preservation

Wrap objects to maintain soil origin.

Karl Lansteiner

Discovered blood typing in 1901.

Blood Types

A, B, AB, O classifications based on antigens.

Population Blood Type Distribution

O: 43%, A: 42%, B: 12%, AB: 3%.

Nature of Blood

Composed of plasma, red/white blood cells, platelets.

Antigens

Substances on red blood cells triggering antibody response.

Serology

Tests to identify blood types using antigens.

Immunoassay Techniques

Tests reacting to drugs in sera.

Hemoglobin Color Test

Reacts to form a deep pink color.

Luminol Test

Produces blue glow in darkness for blood detection.

Precipitin Test

Identifies human or animal blood through antibodies.

Gel Diffusion Test

Matches antigens and antibodies using electric current.

Semen Characteristics

Normal male releases 2.5-6 ml during ejaculation.

Sperm Concentration

Each ml contains over 100 million sperm.

Stain Detection Process

Locate and test stains for sperm presence.

Acid Phosphatase

Enzyme released from prostate during ejaculation.

Prostate Specific Antigen (PSA)

Indicates presence of seminal fluid in evidence.

Sperm Lifespan with Tails

Survives 4-6 hours in vagina after ejaculation.

Sperm Lifespan without Tails

Non-motile sperm lasts 3-6 days in vagina.

Collection of Rape Evidence

Conduct medical exam as soon as possible.

Vaginal Smear

Must dry and be stored for lab analysis.

Buccal Swab

Sample taken from inner cheek for DNA.

Urine Analysis

Tests for drugs like GHB in victims.

Fingernail Scrapings

Collected to find trace evidence from suspect.

Non-Motile Sperm Detection

Can be found up to 72 hours post-intercourse.

Sperm Collection Strategy

Requires careful handling due to fragility.

OK City Bombing

1995 attack resulting in 168 fatalities.

Motive and Modus Operandi (MO)

Key to identifying suspects in arson cases.

Fire Origin Location

Essential for determining cause of fire.

Accelerant Detection

Sniffer dogs can identify fire-starting substances.

Chemical Reaction of Fire

Primarily involves oxidation processes.

Energy in Reactions

Ability to do work or produce heat.

Combustion Definition

Energy released exceeds energy needed to break bonds.

Endothermic Reaction

Requires more energy to break bonds than released.

Ignition Temperature

High temperature needed for gas oxidation.

Pyrolysis

Chemical breakdown of solid fuel to vapor.

Glowing Combustion

Fuel burns without a visible flame.

Spontaneous Combustion

Heat buildup leads to fire without ignition source.

Heat Transfer Methods

Includes conduction, convection, and radiation.

Explosions

Rapid oxidation resulting in violent reactions.

Document Examination

Verifying authenticity of handwritten or printed documents.

Unique Handwriting

Physical attribute that differentiates individuals.

Document Examination Tools

Includes microscopy, photography, and chromatography.

Charred Impressions

Marks left on pad after top sheet removal.

Handwriting Comparisons

Analyzing individual handwriting styles for identification.

General Style

Basic handwriting methods learned in childhood.

Palmer Method

A handwriting technique emphasizing fluidity and speed.

Zaner Bloser Method

A handwriting style focusing on clarity and form.

Variations in Handwriting

Differences in handwriting due to mental functions.

Known Writings

Samples of handwriting from a known individual.

Handwriting Exemplars

Collection of handwriting samples for comparison.

Writing Medium

Type of surface used for writing samples.

Judge's Order

Legal request for handwriting samples from a suspect.

Unconscious Writing

Natural handwriting without intentional alterations.

Angular Variations

Differences in the angle of letters in handwriting.

Slope Variations

Differences in the tilt of handwriting.

Pressure Variations

Differences in the force applied while writing.

Spacing Variations

Differences in letter and word spacing.

Typescript Comparisons

Analyzing printed documents for machine-specific traits.

Infrared Luminescence

Technique to detect modifications on paper.

Indented Writings

Marks left on paper from previous writing.

Electrostatic Detection

Method to reveal indented writing using static electricity.

Thin Layer Chromatography

Technique to analyze and age ink composition.

Forensic Image Acquisition

Creating a copy of a hard drive for analysis.

Hash Algorithm

Mathematical function to verify data integrity.

Operating System

Software managing hardware and user interactions.

Computer Forensics

Field involving analysis and interpretation of digital data.

Visible Data

Apps and files accessible on a computer.

Temporary Files

Backup files that can become permanent.

Internet Cache

Records of websites visited by a user.

Cookies

Data tracking user visits and preferences.

History

Log of sites visited over a time period.

Bookmarks

Saved web addresses for easy access.

IP Address

Unique identifier for a computer on a network.

Hacking

Accessing logs to trace IP connections.

Faraday Bag

Container to block signals from mobile devices.

Mobile Forensics

Analysis of data from mobile devices.

1G Mobile

First generation, only call logs available.

2G Mobile

Digital networks with basic smartphone features.

3G/4G Mobile

High-speed data transfer with internet capabilities.

SIM Card

User-specific card for mobile device connectivity.

SD Card

Expandable storage for mobile devices.

SMS

Short Message Service for text communication.

GPS

Global Positioning System for location tracking.

Temporal Chain

Timeline of events in a forensic investigation.

Causal Chain

Cause and effect relationships in evidence.

Provider Clock

Synchronizes phone time based on location.

Hybrid Crime Assessment

Evaluating crimes with both physical and digital elements.

Wi-Fi Tracking

Records nearby Wi-Fi networks for location data.