Homicide, Autopsy, and Forensic Investigation Fundamentals

Homicide – Classifications

  • First-degree murder: the premeditated killing of another human being with malice, or wrongful intent
  • Felony murder rule (mentioned but details continued on next slide)
  • Second-degree murder: the killing of another without the element of premeditation
  • Manslaughter: the unlawful killing of another without malice or premeditation, either voluntarily or involuntarily
    • Voluntary manslaughter: killing that is done in the heat of passion
    • Involuntary manslaughter: occurs while the perpetrator was involved in the commission of an unlawful act not amounting to a felony

Corpus delicti – Homicide

  • An evidentiary showing of the death of a human being
  • An evidentiary showing of a criminal agency
  • The criminal agency must be the proximate cause of the death; criminal agency means the death was caused by another person's unlawful act or omission

Suspicious Deaths and Autopsy – Overview

  • "Suspicious death" investigations: death with violence or foul play indications; death outside the deceased’s residence; the deceased not under physician care at death
  • Autopsy: major method of detecting murder; autopsy as an extension of the crime scene; offers additional opportunities to search for clues and evidence

Medicolegal Laboratory Services

  • Determine whether a death was caused by criminal agency, and to identify the deceased and the cause of death
  • Report of the postmortem examination consists of:
    • The preamble
    • External appearance
    • Internal examination
    • A reasoned opinion of the cause of death based on the facts found
    • Signature of the examiner

Pathology and Wound Classification

  • Pathologists classify the nature of wounds:
    • Incised wounds
    • Lacerated wounds
    • Contusions
    • Abrasions
    • Gunshot wounds
  • Also assess age of wounds and provide an opinion about the wound

Autopsy Reports – Content

  • Autopsy reports should include:
    • Cause of death
    • If a weapon or substance caused death, the nature of the fatal wounds or injuries
    • Time of death in relation to the wound

Suicide, Accident, or Criminal Homicide?

  • Motive aids in determining the type of death
  • All suspicious deaths require an investigation

Identification of the Victim

  • Identification becomes problematic when death occurs in a public place
  • Partial remains can be identified by:
    • Fingerprints
    • Dental work
    • Bones
    • Surgical procedures

Time of Death – Key Concepts

  • Window of death
  • Algor mortis: after death the body cools
  • Rigor mortis: biochemical changes cause muscle stiffening

Time of Death – Postmortem Changes

  • Postmortem lividity: blood settles to the lowest part of the body
  • Develops noticeably within ~1 hour after death; fully developed within 3–4 hours
  • Appears as blue or reddish marks on the skin

Putrefaction – Two Processes

  • Putrefaction begins at death due to two processes:
    • Autolysis: chemical breakdown of body tissues leading to softening and liquefaction
    • Bacterial action: converts tissue into liquids and gases
  • Greenish-red or blue-green coloration appears within ~36 hours
  • Gases cause the body to swell; environmental factors influence the rate of decomposition

Criminal Homicide Investigation Checklist

  • Stage 1: Crime scene
  • Stage 2: Postscene
  • Stage 3: Lead development
  • Stage 4: Identification and arrest
  • Stage 5: Case preparation

Stage 1 – Crime Scene

  • Evidence: be alert, collect and record
  • Witnesses: identify and interview
  • Suspects: known or unknown identity
  • Crime theory: needs to be developed

Stage 2 – Postscene

  • Cause of death
  • Time of death
  • Criminal agency: means of death (weapon used or recovered)
  • Crime theory

Stage 3 – Lead Development

  • Victim: background and activities
  • Last hours: contacts and activities at/before death
  • Motive: pattern of criminal homicide
  • Opportunities: determine known and unknown persons

Stage 4 – Identification and Arrest

  • Identification of killer: review evidence
  • Focus case
  • Negative evidence: alibi, self-defense, intent, records
  • Arrest

Stage 5 – Case Preparation

  • Final crime theory
  • Review evidence
  • Reinvestigate

Patterns of Criminal Homicide

  • The anger killing
  • The triangle killing
  • The revenge or jealousy killing
  • Killing for profit
  • The random killing
  • Murder–suicide
  • Sex and sadism
  • Felony murder

Motive for Murder: Relationships

  • Spouse (or ex-)
  • Common-law spouse (or ex-)
  • Boyfriend; girlfriend (or ex-)
  • Live-in boyfriend; girlfriend (or ex-)
  • Sister; brother
  • Mother; father
  • Daughter; son

Motive for Murder: Relationships (continued)

  • Other relative
  • Friend of family; relative
  • Neighbor
  • Business associate
  • Acquaintance
  • Seen before (as "known from neighborhood")

Multicide – Definitions

  • Multicide: killing of a number of victims by one or more persons working in concert
    • Mass murder: homicide of four or more victims during a single event at one location
    • Spree murder: killing of three or more persons within a relatively short time frame
  • Multicide (continued):
    • Serial murder: two or more separate murders when an individual, acting alone or with another, commits multiple homicides over a period of time with breaks between each murder event

Serial Murderer Typologies

  • Visionary serial killer
  • Mission serial killer
  • Hedonistic serial killer
  • Power and control serial killer

Stalking – Types of Stalkers

  • Celebrity stalker: victim known on an impersonal level (actor, sports star)
  • Lust stalker: predatory sex, escalates to murder
  • Hit stalker: professional killer
  • Love-scorned stalker: intends violence against known victim
  • Domestic stalker: ex-lover or spouse
  • Political stalker: victim is a stranger to the assailant

Assaults and Related Offenses

  • Assault: unlawful attempt, coupled with present ability, to commit injury on the person of another
  • Battery: unlawful beating or wrongful harm inflicted on a human being without consent
  • Violent injury equals force in assault cases
  • Aggravated assault: assault with a deadly weapon or when serious injuries are inflicted
  • Other related offenses: altercations, disorderly conduct, disturbing the peace

Child Abuse – Definition and Types

  • Child abuse: intentional and deliberate assault upon a child in which serious bodily injury is inflicted by a parent, foster parent, babysitter, day-care worker, or other non-parental caregiver
  • Serious bodily injury is the standard that separates abuse from discipline
  • Burn injuries constitute about 10% of child abuse cases
  • Deliberate immersion burn: uniform depth; result from a child falling into or being placed into hot liquid
  • Contact burns: caused by flames or hot solid objects (e.g., cigarette burns, iron burns)
  • Munchausen syndrome: psychological disorder in which the patient fabricates symptoms of disease or injury
  • Munchausen syndrome by proxy: parent or caregiver induces illness or injures child to draw medical attention

Indicators Linking Injuries to Child Abuse

  • Delays in seeking medical care
  • Injuries not reported by parent or guardian
  • Bruises or broken bones in an infant
  • Age dating of bruises indicating injuries at different times

Shaken Baby Syndrome and SIDS

  • Shaken baby syndrome: occurs primarily in children 18 months of age or younger; retinal hemorrhage is a hallmark
  • Sudden Infant Death Syndrome (SIDS)