Criminal Investigations

1
Criminal Investigations

• Death Investigations
• Chapter 7

2
Introduction

• A basic requirement in a homicide investigation
  is to establish whether death was caused by a
  criminal action
• Statistically, murder is the least significant of
  the Index Crimes
• Homicides continue to receive the most attention
  by police, not only because they are considered
  the most serious crime but also because they are
  complex cases to investigate

3
Classification

• The four types of death
• NONCRIMINAL
• Natural
• Accidental
• Suicide
• NONCRIMINAL OR CRIMINAL
• Homicide

4
Suicide

• Suicide is the intentional taking of ones own
  life

5
Homicide

• Is the killing of one person by another
• Classification of homicides
• Criminal-felonious
• Murder-voluntary and involuntary
• Noncriminal- nonfelonious
• Excusable homicide
• Justifiable homicide

6
Murder

• First degree-premeditated and intentional, or
  while committing or attempting to commit a felony
• Second degree-intentional but not premeditated
• Third gegree-neither intentional nor
  premeditated, but the result of an immenently
  dangerous act

7
Manslaughter

• Voluntary-intentional homicide caused by intense
  passion resulting from adequate provocation
• Involuntary-unintentional homicide caused by
  criminal (culpable) negligence

8
Noncriminal Homicide

• Excusable homicide-is the unintentional, truly
  accidental killing of another person
• Justifiable homicide-is killing another person
  under authorization of the law

9
Premeditation

• Is considering, planning or preparing for an act,
  no matter how briefly, before committing it
• Is the element of first-degree murder that sets
  it apart from all other classifications

10
Elements of the Crime

• Causing the death of another human
• Premeditation
• Intent to effect the death of another person
• Adequately provoked intent resulting from heat of
  passion
• While committing or attempting to commit a felony
• While committing or attempting to commit a crime
  not a felony

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Elements of the Crime Cont.

• Culpable negligence or depravity
• Negligence

12
Challenges in Investigation

• Challenges in homicide investigations include
  pressure by the media and the public, the
  difficulty of establishing that a crime has been
  committed, identifying the victim and
  establishing the cause and time of death

13
Suicide

• More Americans die by suicide than by homicide
• 15 of people with major depression take their
  own lives
• 15 of people who suffer from schizophrenia take
  their own lives
• 85 of suicides are premeditated
• 90 of those who take their lives communicate
  their intentions to someone they know

14
Suicide by Police

• A situation in which a person decides he or she
  wants to die but does not want to pull the
  trigger
• Suicide by cop offender profiles indicate that
  such subjects have a poor self-image, feel a
  sense of guilt for great harm they have caused,
  talk about death and express a desire to be with
  deceased loved ones, speak of a higher being, are
  aggressively confrontational with police and
  posses an unloaded or nonfunctioning gun

15
Suicide of Police Officers

• Police officers commit suicide more than any
  other professional group, and the incidence is
  increasing
• Police officers are more than twice as likely to
  kill themselves as the general population

16
The Preliminary Investigation

• The first priority is to give emergency aid to
  the victim if he or she is still alive or to
  determine that death has occurred

17
Determining That Death Has Occurred

• Signs of death include lack of breathing, lack of
  heartbeat, lack of flushing of the fingernail bed
  when pressure is applied to the nail and then
  released and failure of the eyelids to close
  after being gently lifted

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The Focus of the Homicide Investigation

• Identify the victim
• Establish the time of death
• Establish the cause of and the method used to
  produce death
• Develop a suspect

19
Discovering and Identifying the Victim

• Homicide victims are identified by family,
  relatives or acquaintances
• Personal effects, fingerprints, DNA analysis,
  dental and skeletal studies
• Clothing and laundry marks

20
Estimating the Time of Death

• Factors that help in estimating the time of death
  are body temperature, rigor mortis, postmortem
  lividity (liver), appearance of eyes, stomach
  contents, stage of decomposition and evidence
  suggesting a change in the victims normal routine

21
Body Temperature

• Body temperature drops 2 to 3 degrees in the
  first hour after death and 1 to 1 ½ degrees for
  each subsequent hour up to 18 hours

22
Rigor Mortis

• Rigor Mortis
• Appears in head-5 to 6 hours
• Appears in upper body-12 hours
• Appears in entire body-18 hours
• Disappears in same order-36 hours
• A weapon tightly clutched in the victims hand as
  the result of cadaveric spasm indicates suicide

23
Postmortem Lividity

• Starts one-half to three hours after death and is
  congealed in the capillaries in four to five
  hours
• Maximum lividity occurs within ten to twelve
  hours
• The location of lividity can indicate whether a
  body was moved after death

24
Examination of the Eyes

• A partial restriction of the pupil occurs in
  about seven hours
• In twelve hours the cornea appears cloudy

25
Examination of Stomach Contents

• Determine when and what the victim last ate
• If any vomit is present, preserve it as evidence
  and submit it for examination

26
Decomposition

• Adipocere-soapy appearance of a dead body left
  for weeks in a hot, moist location
• Mummification-complete dehydration of all body
  tissues that occurs when a cadaver is left in an
  extremely dry, hot area

27
Effects of Water

• A dead body usually sinks in water and remains
  immersed for eight to ten days in warm water or
  two to three weeks in cold water
• It then rises to the surface unless restricted
• The outer skin loosens in five to six days, and
  the nails separate in two to three weeks

28
Unnatural Causes of Death and Method Used

• Among the most common causes of unnatural death
  are gunshot wounds, stabbing and cutting wounds,
  blows form blunt instruments, asphyxia induced by
  choking, drowning, hanging, smothering,
  strangulation, gases or poisons, poisoning and
  drug overdose, burning, explosions, electric
  shock, and lightening

29
Gunshot Suicide Indicators

• Gun held against skin
• Wound in mouth or in right temple if victim is
  right handed and left temple if left handed
• Not shot through clothing, unless shot in the
  chest
• Weapon present, especially if tightly held in hand

30
Gunshot Murder Indicators

• Gun fired from more than a few inches away
• Angle or location that rules out self-infliction
• Shot through clothing
• No weapon present

31
Defense Wounds

• Cuts on the hands , arms and legs-result when the
  victim attempts to ward off the attacker

32
Cutting Suicide Indicators

• Hesitation wounds
• Wounds under clothing
• Weapon present, especially if tightly clutched
• Usually wounds at throat, wrists or ankles
• Seldom disfigurement
• Body not moved

33
Cutting Murder Indicators

• Defense wounds
• Wounds through clothing
• No weapon present
• Usually injuries to vital organs
• Disfigurement
• Body moved

34
Asphyxiation Deaths

• Most cases of choking, drowning and smothering
  are accidental
• Most cases of hanging are suicides
• Most cases of strangulation are murder

35
Poisoning

• Toxicology-the study of poison
• Poisoning deaths can be accidental, suicide or
  murder
• Most deaths caused by burning, explosions,
  electrocution and lightening are accidental
• Although burning is sometimes used in an attempt
  to disguise murder

36
The Victim

• The victims background provides information
  about whether the death was an accident, suicide
  or homicide
• If a homicide, the background often provides
  leads to a suspect
• Evidence on the victims body can also provide
  important leads

37
Suspects

• Determine the motive for a killing because it
  provides leads to suspects and strong
  circumstantial evidence against a suspect
• Mass murder-occurs when multiple victims are
  killed in a single incident by one or a few
  suspects
• Serial murder-is the killing of three or more
  separate victims with a cooling off period
  between the killings
• Lust murder-is a sex-related homicide involving a
  sadistic, deviant assault

38
Physical Evidence

• Physical evidence in a homicide includes
• A weapon
• A body
• Blood
• Hairs
• fibers

39
The Medical Examination

• The medical examination provides evidence related
  to the cause and time of death and to the
  presence of drugs or alcohol