The Murder Scene: Death

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The Murder Scene Death Autopsies

• Chapter 2
• OConnor/Forensics

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The body

• The most important piece of evidence in a crime
  scene that resulted in death is the body.

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Who Investigates?

• Primarily the Forensic Pathologist
• Aided by
• Forensic Anthropologist
• Forensic Entomologist

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Role of Forensic Pathologist(in their role as
coroner)

• They must answer these basic questions
• Who is the victim?
• What injuries are present?
• When did the injuries occur?
• Why how were the injuries produced?
• What is the cause of death?
• If observation cant answer these questions, than
  an autopsy must be performed.

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5 Classifications of cause of death

• Natural
• Homicide
• Suicide
• Accident
• undetermined

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Remember!!

• Sometimes things are not as they first appear
• ex. Apparent suicide as murder cover-up.
• Sometimes things are simple and there is not more
  to it than what first appears.
• Ex. a rock near a body is just a rock, not a
  murder weapon

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Estimating time of death

• After a human body expires it goes through
  several stages of decomposition.
• It is necessary to determine time of death in a
  crime.

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Livor mortis

• a settling of the blood in the lower portion of
  the body, causing a purplish red discoloration of
  the skin when the heart is no longer pumping the
  blood, heavy red blood cells sink due to gravity.
  This discoloration does not occur in the areas of
  the body that are in contact with the ground or
  another object.
• starts 20 minutes to 3 hours after death is
  congealed in the capillaries in 4 to 5 hours.
• It can also be used by forensic investigators to
  determine whether or not a body has been moved.

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Rigor mortis

• It commences after around 3 hours, reaching
  maximum stiffness after 12 hours, gradually
  dissipates until approximately 72 hours after
  death. Rigor mortis occurs due to changes in the
  physiology of muscles when aerobic respiration
  ceases.

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Algor Mortis

• the rate at which a body cools after death.
• affected by the physiology of the individual
  (age, weight, illness,) the conditions of the
  environment (temperature, clothing, surface,
  activity prior to death).
• After the first hour to a period of about 6 hrs
  postmortem, a body will generally cool at the
  rate of 1.5 F for each hour after death.
• The preferred time window for evaluating algor
  mortis is within the first several hours after
  death. Beyond that, the rate of cooling becomes
  less less accurate as the body temperature
  approaches equilibrium with that of its
  environment.

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Tour of a morgue

• interactive at morgue with Dr. G

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Interactive Autopsy

• Discovery Health Autopsies

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Forensic Anthropology

• Skeletal detectives
• Examination of bones may reveal
• Sex, approximate age, race skeletal injury.
• Used not only in crimes, but also for individual
  identification in mass tragedies, like a plane
  crash.

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Forensic Reconstruction
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Computer Aided Reconstruction
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1994 tourist disappearance
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Body found in a shallow grave in Capetown
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Forensic Entomology

• is the science of determining a time frame
  and/or circumstance from the empirical evidence
  of insect activity on or around the site in
  question.
• A time of death can be reasonably determined by
  factoring in ambient temperature , availability
  of corpse to insects, and the progress of blowfly
  larvae through their life cycle on that corpse.
• Approximately fourteen days is necessary for a
  blowfly to go from egg to adult.

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Beetle Larvae

• are more variable in form than fly larvae,
  there is more variation between species in the
  number of larval instars (stage of development
  between moulting) - up to fourteen. Beetles
  associated with carrion live in an ephemeral
  environment and tend to have short larval
  development times with only two or three instars.
  Most beetle larvae have chewing mouthparts and
  they feed on a variety of foods associated with
  corpses.
• Some are specialist predators, feeding on fly
  larvae, while others feed on dry flesh, skin,
  ligaments and hair.

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Stages of decomposition as seen in piglets

• Why piglets?
• A 40 kg pig resembles a human body in its fat
  distribution, cover of hair and ability to
  attract insects. These factors make pigs the next
  best things to humans when it comes to
  understanding the process of decay of the human
  body.
• The pigs in this website are newborn piglets
  (weighing about 1.5 kg) that have been
  accidentally crushed by their mothers - a key
  cause of death of piglets. Their bodies have been
  donated to science.

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Stage 1- living pig
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Stage 2 Initial decay - 0 to 3 days after death
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Stage 3 Putrefaction - 4 to 10 days after death
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Stage 4 Black putrefaction - 10 to 20 days after
death
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Stage 5 Butyric fermentation - 20 to 50 days
after death
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Stage 6 Dry decay - 50-365 days after death
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Science reveals secrets of death