The Murder Scene: The Murder Scene: Death & AutopsiesDeath & Autopsies

Chapter 2Chapter 2

O’Connor/ForensicsO’Connor/Forensics

The bodyThe body

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

Who Investigates?Who Investigates?

►Primarily the Forensic PathologistPrimarily the Forensic Pathologist

Aided by:Aided by:►Forensic AnthropologistForensic Anthropologist►Forensic EntomologistForensic Entomologist

Role of Forensic PathologistRole of Forensic Pathologist(in their role as coroner)(in their role as coroner)

►They must answer these basic questions:They must answer these basic questions:►Who is the victim?Who is the victim?►What injuries are present?What injuries are present?►When did the injuries occur?When did the injuries occur?►Why & how were the injuries produced?Why & how were the injuries produced?►What is the cause of death?What is the cause of death?► If observation can’t answer these If observation can’t answer these

questions, than an autopsy must be questions, than an autopsy must be performed.performed.

5 Classifications of cause of 5 Classifications of cause of deathdeath

►NaturalNatural►HomicideHomicide►SuicideSuicide►AccidentAccident►undeterminedundetermined

Remember!!Remember!!

►Sometimes things are not as they first Sometimes things are not as they first appear appear

►ex. Apparent suicide as murder cover-up.ex. Apparent suicide as murder cover-up.

►Sometimes things are simple and there is Sometimes things are simple and there is not more to it than what first appears. not more to it than what first appears.

►Ex. a rock near a body is just a rock, not Ex. a rock near a body is just a rock, not a murder weapona murder weapon

Estimating time of deathEstimating time of death

►After a human body expires it goes After a human body expires it goes through several stages of through several stages of decomposition.decomposition.

► It is necessary to determine time of It is necessary to determine time of death in a crime.death in a crime.

Livor mortisLivor mortis► a settling of the blood in the lower portion of the a settling of the blood in the lower portion of the

body, causing a purplish red discoloration of the body, causing a purplish red discoloration of the skin: when the heart is no longer pumping the skin: when the heart is no longer pumping the blood, heavy red blood cells sink due to gravity. blood, heavy red blood cells sink due to gravity. This discoloration does not occur in the areas of This discoloration does not occur in the areas of the body that are in contact with the ground or the body that are in contact with the ground or another object. another object.

► starts 20 minutes to 3 hours after death & is starts 20 minutes to 3 hours after death & is congealed in the capillaries in 4 to 5 hours. congealed in the capillaries in 4 to 5 hours.

► It can also be used by forensic investigators to It can also be used by forensic investigators to determine whether or not a body has been moved.determine whether or not a body has been moved.

Rigor mortisRigor mortis

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

Algor MortisAlgor Mortis► the rate at which a body cools after death. the rate at which a body cools after death. ► affected by the physiology of the individual affected by the physiology of the individual

(age, weight, illness,) & the conditions of the (age, weight, illness,) & the conditions of the environment (temperature, clothing, surface, environment (temperature, clothing, surface, activity prior to death). activity prior to death).

► After the first hour to a period of about 6 hrs After the first hour to a period of about 6 hrs postmortem, a body will generally cool at the postmortem, a body will generally cool at the rate of 1.5° F for each hour after death. rate of 1.5° F for each hour after death.

► The preferred time window for evaluating algor The preferred time window for evaluating algor mortis is within the first several hours after mortis is within the first several hours after death. Beyond that, the rate of cooling death. Beyond that, the rate of cooling becomes less & less accurate as the body becomes less & less accurate as the body temperature approaches equilibrium with that temperature approaches equilibrium with that of its environment. of its environment.

TOUR OF A MORGUETOUR OF A MORGUE

interactive at morgue with Dr. G

Interactive AutopsyInteractive Autopsy

►Discovery Health Autopsies

Forensic AnthropologyForensic Anthropology►Skeletal detectivesSkeletal detectives►Examination of bones may reveal:Examination of bones may reveal:►Sex, approximate age, race & skeletal Sex, approximate age, race & skeletal

injury.injury.►Used not only in crimes, but also for Used not only in crimes, but also for

individual identification in mass individual identification in mass tragedies, like a plane crash.tragedies, like a plane crash.

Forensic ReconstructionForensic Reconstruction

Computer Aided Computer Aided ReconstructionReconstruction

1994 tourist disappearance1994 tourist disappearance

Body found in a shallow grave in Body found in a shallow grave in CapetownCapetown

Forensic EntomologyForensic Entomology is the science of determining a time is the science of determining a time

frame and/or circumstance from the frame and/or circumstance from the empirical evidence of insect activity on or empirical evidence of insect activity on or around the site in question. around the site in question.

A time of death can be reasonably A time of death can be reasonably determined by factoring in ambient determined by factoring in ambient temperature , availability of corpse to temperature , availability of corpse to insects, and the progress of blowfly insects, and the progress of blowfly larvae through their life cycle on that larvae through their life cycle on that corpse. corpse.

Approximately fourteen days is necessary Approximately fourteen days is necessary for a blowfly to go from egg to adult.for a blowfly to go from egg to adult.

Beetle LarvaeBeetle Larvae► are more variable in form than are more variable in form than

fly larvae, & there is more fly larvae, & there is more variation between species in the variation between species in the number of larval instars (stage of number of larval instars (stage of development between moulting) development between moulting) - up to fourteen. Beetles - up to fourteen. Beetles associated with carrion live in an associated with carrion live in an ephemeral environment and ephemeral environment and tend to have short larval tend to have short larval development times with only two development times with only two or three instars. Most beetle or three instars. Most beetle larvae have chewing mouthparts larvae have chewing mouthparts and they feed on a variety of and they feed on a variety of foods associated with corpses. foods associated with corpses.

► Some are specialist predators, Some are specialist predators, feeding on fly larvae, while feeding on fly larvae, while others feed on dry flesh, skin, others feed on dry flesh, skin, ligaments and hair. ligaments and hair.

Stages of decomposition as Stages of decomposition as seen in pigletsseen in piglets► Why piglets? Why piglets?

► A 40 kg pig resembles a human body in its fat A 40 kg pig resembles a human body in its fat distribution, cover of hair and ability to attract distribution, cover of hair and ability to attract insects. These factors make pigs the next best insects. These factors make pigs the next best things to humans when it comes to things to humans when it comes to understanding the process of decay of the understanding the process of decay of the human body. human body.

► The pigs in this website are newborn piglets The pigs in this website are newborn piglets (weighing about 1.5 kg) that have been (weighing about 1.5 kg) that have been accidentally crushed by their mothers - a key accidentally crushed by their mothers - a key cause of death of piglets. Their bodies have cause of death of piglets. Their bodies have been donated to science. been donated to science.

Stage 1- living pigStage 1- living pig

Stage 2: Initial decay - 0 to 3 Stage 2: Initial decay - 0 to 3 days after death days after death

Stage 3: Putrefaction - 4 to 10 Stage 3: Putrefaction - 4 to 10 days after death days after death

Stage 4: Black putrefaction - Stage 4: Black putrefaction - 10 to 20 days after death 10 to 20 days after death

Stage 5: Butyric fermentation - Stage 5: Butyric fermentation - 20 to 50 days after death 20 to 50 days after death

Stage 6: Dry decay - 50-365 Stage 6: Dry decay - 50-365 days after death days after death

Science reveals secrets of Science reveals secrets of deathdeath