Study guide exam 1
What is Locard’s principle?
- Locard’s principle states that any two objects that come into contact with each other will leave a mark upon the other; criminals always bring evidence into a scene and always take evidence with them, even if not intentionally
What do Forensic anthropologists study?
- Material that law enforcement has jurisdiction over- includes burnt remains, mass graves, decomposed, or dismembered bodies
What’s the primary objective in a FA’s examination?
- Make a biological profile that can characterize a person based on factors like their age, biological sex, height and race
- Highlight any identifying features on the body/bone like disease, cut marks, or any other damage
- Time of death
- Find and recover potentially scattered evidence
- Remember that forensic anthropologists are not qualified to determine cause of death. That falls in the medical examiner’s scope of practice.
State the four periods in forensic anthroplogy (US)
- Formative (1849-1938)
- Consolidation (1939-71)
- Modern (1972-1999)
- New millennium (2000- present)
Details of the Parkman murder:
- Paul Revere was able to ID Dr. Parkman’s damaged (burnt/dismembered) remains by identifying the silver dentures he made for Parkman. This lead to Warren’s arrest after the janitor reported suspicious activity.
- Oliver Wendell Homes and Jeffries Wyman were the skeletal analysts in this case
- Father of modern anthropology
- Was the first to lecture on forensic analyses of human bodies within a legal context Don't forget about the age old question of What is the background of andrew johnson?
Importance of skeletal collections:
- Allowed for anatomists to study a wide variety of human skeletons
- These collections were “known collections”, i.e. had recorded details about the people who donated their bodies, like age, sex, medical history, etc. - Hamman-Todd collection at the Cleveland Museum of Natural History - Terry collection at the Smithsonian
Problems with the skeletal collection:
- Doesn’t account for secular trends (most notable is height increasing over time)
- Many of the donated bodies were from people who had poor nutrition/diseases, so it doesn’t reflect accurately on a population with good health/nutrition If you want to learn more check out What are the features of earth's movements?
- Juveniles aren’t normally donated, more older than young bodies
Forensic anthropology in a human right’s context:
- Central identification Laboratory (CILHI) wanted to identify missing WWII soldiers’ bodies in present day peaceful areas. If you want to learn more check out Which specialized roles were added in ad agencies during the early 20th century?
The body farm:
- Established at the University of Tennessee in 1980 by Dr. William Bass - Purpose was to study the effect of decomposition in different contexts on the human body
- Started with pig corpses but later started using donated human bodies - Drawback- decomposition has to be studied in areas with regional variation
The difference between coroners and Medical examiners: If you want to learn more check out Who unified mesopotamia back in 1900 bc?
- MEs are forensic pathologists, i.e. they have a medical license and have been trained at a medical school to conduct autopsies and determine the cause of death.
o Usually appointed by a governor
o Have full jurisdiction over the body
o Have the power to conduct an autopsy without the family’s consent o They identify the decedent and give a cause/time of death
- Coroners are not required to have medical expertise
o They can determine if an autopsy is necessary
o Call in MEs if they are not licensed to perform autopsies
o Coroner systems are usually used in areas with a lower crime rate, small caseload or few pathologists.
The two types of death:
- Attended deaths: physician was present when the person died, or they know a clear cause of death, and have adequate medical history to support their
claim. There is no suspicion concerning the death, but family members have the right to request an autopsy
- Unattended deaths: an unanticipated death caused by injury, trauma, or unavailable cause of death
o This requires an ME /coroner investigation to rule out potential foul play We also discuss several other topics like What si the contribution of gustav fechner in the field of psychology?
- Clinical autopsies are done in a hospital setting by a clinical pathologist - Forensic autopsies are done for a medico-legal purpose in the case of an unnatural death
- Reason for conducting:
o Cause of death and manner of death identification
o Time of death
o Identification of body and evidence
o Recording factual evidence to provide police or prosecutors
o Protecting innocents and prosecuting (the testimonials of MEs carry a lot of weight as they are the expert witness in the case)
Difference between cause and manner of death:
- The cause of death is WHY someone died (like being shot in the head); medical, anatomically correct diagnosis for the death We also discuss several other topics like What is the difference between conjunct and disjunct?
- Manner is HOW the death happened
o Natural causes
Human remains scenes:
- Usually come upon the scene by accident (animal digs up bones, shallow gravesites, bodies recovered during farm work)
- The old scene can be reconstructed based on evidence
- Recovering body and its parts is hard
- Cases are usually ‘cold’ , i.e. no active suspect in mind
- Law enforcement officials don’t usually have training in field recovery - The scene is larger than it seems
- Total recovery is the objective
- Forensic archaeological techniques should be implemented
- Contextual evidence is important
- The scene is permanently altered whenever recovery occurs, therefore its important to use minimally invasive techniques
Remember that the body is the primary evidence at a crime scene (corpus delecti) Scene types:
- Enclosed- in which bodies are confined to a certain area
- Open- no indicator of where the body or evidence trail ends (remains can be scattered or moved by natural forces)
Indication of remains:
- Clandestine graves
- Surface variations in the soil
- Color/chemical composition change in the soil
- Variation in vegetation
- Scavenging by rodents/predators
- Visible evidence
Methods of non-invasive searches:
- Radars (ground penetration with radio waves)
- Magnetometry (recovery of metallic objects)
- Infrared photography
- Cadaver dogs
Invasive search methods end up irreversibly affecting the crime scene. They have the potential to damage evidence, therefore avoid until completely necessary
- When remains are found, scene must be mapped for future use by setting up a datum or fixed point first. Then establish the body’s positon on the grid, and surrounding objects as reference points
When moving remains:
- Move the body the shortest amount of distance possible
- Avoid contaminating the scene with external biological remains - Put the remains in a body bag or cover with a tarp/clean sheet to protect from damage and to maintain privacy
- Treat the body with respect!
- Make sure the case details remain confidential until the authorities decide to release details
- Findings seriously affect the lives of the decedent’s family
- Provide an honest account of details concerning the case (clarify data and interpretation in court)
- Don’t overstate your credentials; stay within your scope of practice
Bodies move from the ME’s office to forensic labs, then return to ME’s office
- The exact location and details of the evidence has to be known - Only those who are qualified can access the body
- Protect/secure against evidence tampering and damage
Maceration- the process in which soft tissue is removed from remains to produce a clean, dry skeleton for analysis
Process of maceration
- Soft tissues are removed by hand
- Disarticulate the skeleton
- Use hot water to soften remaining tissues
- Remove remaining tissue and clean off the bones
o Dermestid beetles are used to clean up tissue that includes cartilage and tendons- strips a skeleton bare; noninvasive method of tissue removal
After the remains are prepared, the evidence has to be catalogued, photographed and radiographed to make sure all details are recorded
- Includes any damage or abnormalities noted
What is the postmortem interval?
- PMI is the amount of time elapsed since death. Breaks down into three time periods:
o First 24 hours- specific biological changes occur in the body
o 1 day-1 month – decomposition and damage by insects occurs o Months- years- taphonomic changes develop (generalized damage over time due to environmental exposure)
What specific changes happen in the first 24 hours?
- Algor mortis- body losing heat
- Rigor mortis- muscle stiffness caused by contraction
- Livor mortis- blood pooling causing discoloration
o These three criteria are used for fully fleshed bodies
- Autolysis- acid in the digestive tract starts to digest the internal organs in the stomach cavity
- Putrefaction- bacteria and microorganisms grow undeterred, thus decomposing the body and causing bloating by releasing gas