HOSA: Crime Scene and Death Investigation

Rules of Evidence

Exclusionary rules that filter out irrelevent/prejudiced information

Frye Standard

New methods must be generally accepted by scientists

Federal Rules of Evidence

Allows expert witnesses to explain techniques in court

Daubert Trilogy

Judge becomes gatekeeper to determine the admissibility of evidence while following a court framework

Direct Evidence

Evidence that establishes something without further work (eyewitness testimony)

Circumstantial Evidence

Evidence that requires reasonable inferences to be drawn (DNA found at a crime scene)

Class characteristic evidence

Evidence that doesn't indicate a specific individual (shell casings, sneaker prints)

Individual characteristic evidence

Evidence that does indicate a specific individual (fingerprints, DNA)

Associative Evidence

Things found at the crime scene that can be matched to an exemplar (standard)

Biological Evidence

Human (or other) tissues used to identify a person or animal. Includes DNA testing.

Chemical Evidence

Includes drugs, explosive, toxicology ect...

Trace Evidence

Random stuff left at a crime scene and taken from a crime scene due to Locard's Exchange Principle

Fingerprint Evidence

Fingerprints and their identification and developments

Impression Evidence

Impressions on the ground caused by footwear, tires, ect...

Firearm and Tool Mark Evidence

Fired bullets, casings, Gun Powder Residue, impressions left by tools ect...

Questioned Documents

Examining documents for forgery

Primary Crime Scene

Site of first criminal activity in a case

Secondary Crime Scene

Site of following criminal activity in a case

Macroscopic Crime Scene

The whole crime scene

Microscopic Crime Scene

Small, contained parts of the crime scene

Link Search

One type of evidence leads to another ( most common)

Line Search

Work horizontally across an area with large groups of volunteers (Best outdoors, requires a large amount of man power)

Grid Search

Work horizontally and vertically across an area with large groups of volunteers (time consuming but effective)

Zone Search

Divide the area to be searched into zones and assign each person/team a zone (Best used in houses on search warrents).

Wheel Search

Spread out like spokes on a wheel from the center. (best used in a small circular crime scene, uncommon)

Spiral Search

Work outwards in concentric circles (Limited best used in the water)

Coroner

Government agent responsible for performing death investigations. Typical in rural areas

Medical Examiner

Appointed to work on death investigations. Required to be licensed to practice medicine

Cause of Death

Diseases/trauma that was the direct cause of death

Mechanism of Death

Specific occurrence that caused death

Manner of Death

How the cause of death came about (Natural, Accidental, Homicide, Suicide)

Rigor Mortis

Stiffening of the muscles after death

4-36 hours after death

Time frame for rigor mortis

Livor Mortis

Discoloration of the body after death due to settling of the red blood cells

12-36 hours

Time frame for Livor Mortis

Algor Mortis

Cooling of body after death

37 C

Normal human body temperature

1.5 F per hour

Time frame for cooling of a nude body a 20 C

Incised wounds

Injury produced with a sharp instrument and characterized by lack of surface abrasion and bridging vessels/nerves

Autopsy

Dissection to determine cause of death

Mechanical Trauma

Occurs when something with force breaks tissues

Sharp Force Trauma

Occurs when a sharp object breaks tissues. Produces incised wounds

Blunt Force Trauma

Occurs when a dull object with a large amount of force breaks tissues. Produces lacerations

Penetrating gunshot

Gunshot with no exit wound

Perforating gunshot

Gunshot with an exit wound

Contact gunshot

Leaves large lacerations, blackened skin, and carboxymyglobin.

Distant gunshot

Circular hole in skin, defective and abraded skin

Exit wounds

Typically the larger and more lacerated gunshot wounds, except in contact gunshots

Chemical Trauma

Deaths resulting from drugs/poisons

Thermal Trauma

Deaths resulting from excessive temperatures

Hypothermia

Excessive cold

Hyperthermia

Excessive heat

Electrical Trauma

Passage of electricity through a person

Ventricular Fibrillation

Quivering of the heart, can be caused by low voltage electricity

Tetany

Sustained contraction of the heart, can be caused by high voltage electricity

Asphyxias

Interruption of oxygen to the brain

Drowning

Water in lungs, diatoms in bone marrow

Manual Strangulation

Fracture of thyroid cartilage, bruised strap muscles

Ligature Strangulation

Leaves no fracture of thyroid cartilage only signs are asphyxia and furrow on neck

300 g

Normal heart weight?

Cadaveric Spasm

Forceful muscle contraction at the moment of death

Autolysis

When internal organs, including the brain, self loosen after death

Adipocere

Waxy, grey fat that occurs when bodies are in water

Macerated

Softening and breaking down of skin from prolonged exposure to water

Arteriosclerosis

Hardening of the arteries

Myocardial Infraction

A blockage of the heart that results in the death of heart muscle

Epidural Hemorrhage

Hemorrhage due to trauma between the Dura mater and the skull

Arachnoid

Two thin, filming transparent membranes that cover the brain directly below the mater

Leptomeninges

Almost inseparable combination of the delicate archnoid mater and the pia mater

Floater

Decomposing body. Wet floaters are found in the water, dry floaters are found on land

Contusion

A black and blue bruise

Marbling

Greenish discoloration that begins at the belly button and the numerous veins beneath the skin become visible and may show greenish discoloration. Occurs 3-5 days after death

Subdural Hemorrhage

Blood lies below the dura mater

Pia Mater

The transparent innermost covering of the brain

Dura Mater

Lies just below the surface of the skull. A firm, tough and fibrous membrane that covers the brain.

Pericardium

The sack that surrounds the heart

Duodenum, jejunum, and ileum

Small intestines