1.      Lesson 07: Death Investigations

(Adapted from Chapter 8 of Bennett/Hess text)

 

2.      Basic Requirement

n  Homicide investigators must determine whether a death is the result of criminal action (i.e., whether the death is a criminal homicide)

 

3.      How are deaths classified?

n  Natural

n  Accidental

n  Suicide

n  Homicide

 

4.      What is a homicide and how are homicides classified?

n  A homicide is the killing of one human being by another human being.

n Homicides may be

n  criminal (felonious) or

n  non-criminal (non-felonious)

 

5.      How are non-criminal homicides classified?

n      Justifiable homicide

n     The necessary killing of another person in performance of a legal duty or the exercise of a legal right when the slayer was not at fault

n      Excusable homicide

n     Differs from justifiable homicide in that one who commits an excusable homicide is to some degree at fault but the degree of fault is not enough to constitute a criminal homicide

 

6.      How are criminal homicides classified?

n      Murder

n     Defined by common law as the killing of any human being by another with malice and forethought

n      Manslaughter

n     Defined as a criminal homicide committed under circumstances not severe enough to constitute murder, yet it cannot be classified as either justifiable or excusable homicide

 

7.      How does the KRS classify homicides?

n  Murder

n  Manslaughter First Degree

n  Manslaughter Second Degree

n  Reckless Homicide

 

8.      What is the difference between the cause and manner of death?

n  Cause of death refers to how the death was caused, physiologically

n  Examples:

n  Gunshot wound

n  Stabbing or cutting

n  Blunt force trauma

n  Asphyxia

n  Poisoning/overdose

n  Burning

n  Explosion

n  Electric shock

 

n  Manner of death refers to how the death is classified…

n  Natural

n  Accidental

n  Suicide

n  Homicide

 

9.      Suicide Indicators

n  Hesitation wounds

n  Gunshot wound in mouth or right or left temple (depending on whether right or left handed)

n  Wounds under clothing unless shot in chest

n  Weapon present, especially if tightly clutched

n  Often wounds at throat, wrists, or ankles

n  Seldom disfigurement

 

10.  Hesitation Wounds

n   Self-inflicted after a decision is made not to commit suicide or any tentative cut or wound that is made before the final cut that causes death

n   Usually superficial, sharp, forced skin cuts

n   Often caused by attempts to build up courage before attempting the final, fatal wound

n   Non-fatal, shallow hesitation wounds can also accompany the deeper, sometimes fatal incisions

n   Not always present in cases of suicide, they are typical

n   The presence of hesitation marks alongside or near to the final fatal mark usually indicates a forensic diagnosis of suicide over other possible causes of death

 

11.  Homicide Indicators

n  Defense wounds

n  Wounds through clothing

n  No weapon present

n  Usually injuries to vital organs

n  Disfigurement

n  Body moved

 

12.  Process

n  The basic homicide investigation involves…

n  A crime scene investigation. Important evidence includes weapons, body, blood, hairs, fibers, and any associative and corpus delicti evidence.

n  Identifying the victim.

n  Estimating the time of death.

n  Establishing the cause and manner of death.

n  Developing a suspect.

 

13.  How do we identify the victim?

n  Family, relatives, acquaintances

n  Personal effects

n  Fingerprints

n  DNA

n  Dental/skeletal studies

n  Clothing and laundry marks

n  Missing person files

 

14.  How is the time of death estimated?

n  Information from last person to see victim alive

n  Algor mortis

n  Rigor Mortis

n  Lividity or Livor Mortis

n  Cadaveric spasm

n  Putrefaction

n  Insects

n  Stomach contents

n  Examination of the eyes

 

15.  Rigor Mortis

n   The general stiffening of the body caused by postmortem chemical changes in the muscle tissue.

n   Generally begins 1-4 hours after death.

n   Entire body affected within 6-12 hours.

n   Disappears in 24-36 hours.

n   Affects smaller muscles first (toes/fingers).

 

16.  Lividity or Livor Mortis

n  Discoloration of the skin due to the gravitational settling of the blood after death. Generally begins 30 minutes after death and becomes “fixed” in about 8 to 10 hours. Also helps to tell if a body has been moved.        

 

17.  Putrefaction

n   Decomposition resulting from bacteria within the intestinal tract escaping into other tissues of the body. 

n   The result is gases and other distortion and discoloration of the tissues.

n   Examples are marbling, swelling of the abdomen, fluids leaking from the mouth and nose, emptying of the rectum, and skin blisters.

 

18.  Insects

n   Examinations of stages may reveal information on time of death. For example, a housefly may lay eggs on the eyes, mouth, nostrils, and wounds after death. These eggs become maggots in about 24 hours. Insects and their cocoons should be collected for examination by entomologists.

 

19.  Cadaveric Spasm

n  Stiffening of hands or arms that may take place immediately after death.  Also known as the death grip. Not to be confused with rigor mortis. There is disagreement in the literature as to the existence and significance of cadaveric spasms.

 

20.  Examination of the Eyes

n  Examination of the eyes- Muscle tone in eye disappears and pupils dilate after death. The cornea gets cloudy and the level of potassium rises. Fluid drawn from the eye may indicate time of death.

 

 

21.  Autopsy

An autopsy is a part of the medico-legal examination process. The autopsy may reveal:

n  What type of weapon was employed?

n  If multiple wounds were inflicted, which wound was fatal?

n  How long did the victim live after the injury?

n  What position was the victim in at the time of the assault?

n  Direction of force?

n  Any evidence of struggle?

n  Evidence of rape or sexual assault?

n  Was the deceased under the influence of drugs or alcohol?

 

22.  Defensive Wounds

 

23.  Gunshot Wounds

n  When a bullet strikes a body, the skin is first pushed in and then perforated while in the stretched state. After the bullet has passed, the skin partially returns to its original position, and the entry opening is drawn together and is thus smaller than the diameter of the bullet.

 

24.  Other Observations Regarding Gunshot Wounds

n   Contact shots or wounds may often reveal an irregular or stellate (star shaped) pattern due to escaping gases from the muzzle getting under the skin or garment and causing tears.

n   A halo of smoke is indicative of a discharge of 18 inches or less

n   The presence of scattered specks of unburned or partially burned residues can often be observed in distances of up to 25 inches. Occasionally, specks may be observed up to 36 inches. Ball/powder ammunition may extend this distance to 6-8 feet.

n   At distances greater than 3 feet, the target may only exhibit “bullet wipe” around the perimeter of the entry. Bullet wipe results from the deposit of carbon, dirt, oils, residues and lead wiped off the bullet's surface as it passes through a target.

n   These are only general observations and they may vary according to barrel length, caliber, type of ammunition and the condition of the weapon fired.

 

25.  How can an investigator tell the difference between an entry gunshot wound from an exit gunshot wound?

n   Entry…

n  Generally smaller than exit

n  May be smaller than diameter of bullet

n  Typically round, neat hole with abrasion ring and gray or black ring around the edges

n  Small amount of blood

 

n   Exit…

n  Generally larger than entrance wound

n  Ragged, torn in appearance with shreds of tissue extruding

n  Generally more bloody than entrance wounds

 

26.  Examples

 

27.  Bullet Entry wound – contact range

 

28.  Abrasion ring – contact range

 

29.  Powder tattooing: close range (often less than 25 inches)

 

30.  What may gunshot residue tests tell us?

n  If a subject fired a weapon

 

31.  What else may gunshot residue tests tell us?

n Muzzle to target distance

 

32.  Diagram

 

33.  What are the basic characteristics of cutting wounds?

n  Cutting wounds (also known as incised wounds) are caused by drawing a sharp object over the skin. External bleeding is generally the cause of death. The are not typically as deep as stab wounds.

 

34.  What are the basic characteristics of stab wounds?

n  Stabbing wounds are caused by thrusting actions. They are generally deeper than they are wide. Internal bleeding and damage to internal organs are usually the cause of death.

 

35.  What are the basic characteristics of puncture wounds?

n   Puncture wounds are like stab wounds leaving a small exterior hole but causing a deep wound.

n   Often overlooked but may be very serious in that they may damage internal organs.

n   Puncture wounds are typically inflicted by ice picks, leather punches, and screwdrivers.

 

36.  What type wounds are generally open, irregular shaped tears caused by blunt instruments?

n  Lacerations

 

37.  Asphyxiation

n  Death where body tissues and brain receive insufficient oxygen to support red blood cells resulting in death (choking, drowning, hanging, strangulation)

n  Autoerotic asphyxiation: Accidental death caused by a solitary victim seeking to intensify sexual gratification by constricting oxygen and blood flow to the brain that results in unconsciousness, often by a rope or other ligature.

 

38.  What is the difference between manual and ligature strangulation?

n  Manual by hand

n  Ligature by belt, rope, cord, etc.

 

39.  Asphyxia- homicide, suicide or accidental?

n  Most hangings are suicide

n  Most strangulations are homicide

n  Most cases of choking, drowning and smothering are accidental

 

40.  Mass or Serial Murder?

n  Mass murder…

n  Occurs when multiple victims are killed in a single incident by one or a few suspects.  An example is a sniper who kills several innocent people from on top of a building.

n  Serial murder…  

n  The killing of three or more people with a ‘cooling off’ period between the killings.  An example would be a killer who murders several people in a multi-state area in the course of a year.