Death Investigation

Dr. Jason LinvilleUniversity of Alabama at Birmingham

jglinvil@uab.edu

Summary

Cause and Mechanism of Death Mechanical trauma (gunshot, stabbing) Chemical trauma (overdose, poison) Other

K-Fed sez:

Quiz on Friday.

Death Investigation

Cause of death: disease or injury that initiated the events that led to death

Mechanism of death: Physical abnormality produced by cause of death that is incompatible with life.

Richard Moll has purloined Marsha Warfield’s sack lunch from the set of Night Court 2010.

Examples:

Death Investigation

Richard Moll has purloined Marsha Warfield’s sack lunch from the set of Night Court 2010. Marsha smothers him with a pillow. Richard Moll dies.

Cause of death: smothering

Mechanism of death: asphyxia

Examples:

Death Investigation

William Blake has set Siegfried and Roy’s tiger on fire. Siegfried stabs him in the aorta. The ambulance gets into an accident on the way to the hospital. Blake dies.

Cause of death: stabbing

Mechanism of death: loss of blood

Examples:

Death Investigation

Man shot during robbery. Man stabilizes. Develops pnemonia. Followed by kidney failure, liver failure, heart failure, death. Had prior lung and heart disease, and probably would have survived if not for these diseases.

Cause of death: gun shot

Mechanism of death: heart failure

Examples:

Death Investigation

Determining the manner of death:

Natural Accidental

Homicidal Suicidal

For example, a gunshot could be three of the above choices.

Manner may be undetermined.

Death Investigation

Classification of Traumatic Deaths:

Mechanical Thermal

Chemical Electrical

Death Investigation

Mechanical

Sharp force (knife) Blunt force (gunshot, baseball bat, etc.)

Death Investigation > Traumatic Death

Mechanical (sharp force vs. blunt force)

Sharp force Sharp edges Incised wound

Blunt force Rough edges Laceration

Death Investigation > Traumatic Death

Mechanical (sharp force)

Difficult to determine size of blade from size of wound

Smaller/larger blade may cause larger/smaller wound

Mechanism of death usually loss of blood

Death Investigation > Traumatic Death

Mechanical (blunt force - firearms)

Most common homicidal & suicidal wound in US

Wounds can be:

Damage due more to velocity than mass

Penetrating: entrance wound, no exit wound Perforating: entrance and exit wound

Death Investigation > Traumatic Death

Mechanical (blunt force - firearms)

Escaping gases may affect appearance of wound

Death Investigation > Traumatic Death

Contact or near-contact wound

Gases burn (blacken) skin Gases into wound tears skin

(blown out appearance) Possible head explosion

Death Investigation > Traumatic Death > Mechanical > Firearm Wound

Intermediate range wound

Unburned powder creates stippling around wound.

Death Investigation > Traumatic Death > Mechanical > Firearm Wound

Distance gunshot wound

Circular hole with rim of abraded skin. Note: size of bullet cannot be determined

Death Investigation > Traumatic Death > Mechanical > Firearm Wound

Entrance vs. Exit wound

Typically, entrance wound smaller than exit wound.

Reason: nothing behind exit wound to prevent explosive burst.

Death Investigation > Traumatic Death > Mechanical > Firearm Wound

Entrance vs. Exit wound

Exception is if exit wound is shored. Tight fabrics or body against object prevents the “explosive outburst”.

Shored exit wound looks like entrance wound (which is always shored by body)

Death Investigation > Traumatic Death > Mechanical > Firearm Wound

Damage relates to kinetic energy

Exiting bullet “wastes” kinetic energy Hollow point bullets designed to expand

and stay in body longer; in reality not much difference.

Death Investigation > Traumatic Death > Mechanical > Firearm Wound

Damage due to rebounding tissue

Bullet too fast to tear tissue; pushes tissue aside creating cavity.

Tissue tears upon rebound, along with some surrounding tissue.

Damage about 3x diameter of bullet

Death Investigation > Traumatic Death > Mechanical > Firearm Wound

Mechanical (blunt force – non-firearms)

Most common are car accidents For homicide (beatings) almost always

involves a blow to the head.

Mechanism of death: usually drowning in blood

Death Investigation > Traumatic Death

Mechanical (blunt force – non-firearms)

Rarely will one blow to the head knock a person unconscious.

Book fails to mention vulcans.

Death Investigation > Traumatic Death

Mechanical (blunt force – non-firearms)

Contusion: accumulated blood in tissues outside the blood vessels (internal bleed)

Hematoma: large contusions (blood tumor); goose egg on head

Death Investigation > Traumatic Death

Chemical Trauma

Overdoses: depressants (including alcohol) slow communications. Can cause coma.

Stimulants may cause seizures and death, less common.

Death Investigation > Traumatic Death

Chemical Trauma

Carbon Monoxide: binds hemoglobin, blocks oxygen. Kills by asphyxiation.

Other poisons interfere with a variety of essential biological functions.

Death Investigation > Traumatic Death

Thermal Trauma

Hypothermia: excessive cold

Hyperthermia: excessive heat

Death from fire usually due to carbon monoxide poisoning.

Death Investigation > Traumatic Death

Both hard to diagnose

Electrical Trauma

Heartbeat relies on electrical signals from the brain.

Extremely high voltage causes heart to contract, then start beating again.

Low voltage causes heart to “quiver”, then stop.

Death Investigation > Traumatic Death