Role of a Forensic Autopsy Technician and Related Concepts
Lecture 1: Role of a Forensic Autopsy Technician
Autopsy: Thorough examination performed by a pathologist to determine the cause and manner of death.
Types of autopsy:
Clinical autopsy:
Performed when cause of death (COD) is already known (typically in natural deaths).
Conducted by a pathologist.
Requires consent from the next of kin, who may limit the exam.
Forensic autopsy:
Conducted to determine COD and manner of death (MOD).
Performed by forensic pathologist.
Next of kin does not authorize and cannot limit the exam.
Goals of forensic autopsy:
Determine injuries or diseases that contribute to/cause death.
Detect any medical/surgical errors.
Correlate signs/symptoms to disease and death.
Identify the decedent.
Establish time of death (TOD) and collect trace evidence.
Role of the forensic autopsy technician:
Responsible for assisting the forensic pathologist before, during, and after the autopsy.
Tasks include:
Body preparation
Photography
Organ dissection
Body restoration
Evidence collection
Toxicology assessment
Who gets a forensic autopsy?
Anyone who dies from a non-natural cause automatically comes under examination. Cases include:
Homicide
Suicide
Accidents
Undetermined/suspicious deaths
Includes natural death cases when a physician is uncomfortable or unwilling to sign a death certificate.
Types of autopsy exams:
External examination:
Confirm correct body by checking name and opening the body bag in the presence of two people (ensures chain of custody).
Photograph body upon receipt to document clothing and effects.
Documentation includes:
Rigor mortis, livor mortis, algor mortis
External injuries, scars, tattoos, and other physical findings
Identify and measure entrance/exit gunshot wounds, blunt and sharp force injuries, and other abnormal findings.
Evidence collection diverse items:
Fingerprints and blood spots for DNA collection and preservation.
Fingernails, pubic and head hair samples.
Swabs from hands/fingers, oral, vaginal, and anal.
Projectiles and non-natural artifacts that penetrated the body (e.g., knives).
Drugs or weapons in non-homicide cases are collected and stored for five years until they can be destroyed.
In homicide cases: fingers tested for gunshot residue (GSR), fingernails collected, and all personal effects handed over to police while establishing chain of custody.
Following the autopsy, clothing and personal effects are collected, documented, and stored appropriately.
Internal examination:
Involves examining the internal body cavity.
Procedure:
Body opened via a Y-shaped incision.
Begins at each shoulder, meets at the sternum, and ends at the pubis.
Two methods to remove internal organs:
Virchow technique: Removes organs one by one.
Rokitansky technique: All internal organs (except the brain) are removed while still connected.
Weights and descriptions of removed organs recorded; organs sliced to reveal possible underlying pathologies.
Removing the brain:
Scalp reflected, cranium removed, dura stripped, pituitary gland removed.
Body restoration:
After organ dissection, remaining organs placed in a red bag in chest/abdominal cavity before sewing body together.
Body is washed, returned to body bag, cooled for funeral home pickup for final disposition.
Toxicology:
When COD cannot be determined at autopsy, it is listed as “pending toxicology.”
Various samples (blood, urine, vitreous, bile, stomach contents) sent to labs for testing.
Testing results can reveal illicit drugs or prescribed medications.
Blood stored in specific tubes to prevent clotting and results sent to national medical services (NMS).
Quick-tox test alerts presence of 11 possible drug metabolites; negative results may lead to fentanyl testing.
Specialized kits (e.g., PA state tox kit for MVAs, GOL kit for organ donor cases).
Lecture 2: History of Forensic Autopsy
Ancient Civilizations:
Egypt: Early civilization applying forensic practices; priests served as both physicians and lawyers.
King Ptolemy established the university and library of Alexandria where medical officials were authorized to dissect and examine bodies.
Ancient Greeks: Base medicine on four humors related to organ function:
Four humors: Blood, phlegm, yellow bile, black bile.
Key Figures:
Herophilus: Father of anatomy; performed first known autopsies and characterized diseases/anatomy.
Galen: Systemized Hippocratic tradition, correlating patient complaints with examination findings.
Significant Historical Events:
Autopsy of Julius Caesar: Earliest recorded autopsy, leading to the Latin term forensics, meaning “before the forum.”
Justinian Enactments: Regulated medical practices; proof of competence required and enhanced the role of medical experts in lawful interpretations.
Formalization of Coroners:
In 1194 England, coroners formalized duties included conducting inquests, taxation, and arrest warrants for murder investigations.
Forensic Medicine Development:
Pablo Zacchias: Published volumes on forensic medicine; regarded as its father.
Caroline Code (1533): Required expert medical testimony for serious crimes.
East Asia:
Investigators known as kenshi, similar to European coroners.
Forensic Education Establishment:
University of Edinburgh: Chair of forensic medicine established in 1803.
Historical Progression in America:
English coroner system brought over by colonists; the first inquest recorded in 1635.
Transition from appointed to elected coroners.
Medical Examiners: First recognized official use in Massachusetts in 1877; system adopted in New York City in 1918 replacing the coroner’s office.
Maryland established the first state medical examiner’s office in 1939.
Types of Autopsies:
Hospital (Clinical) Autopsies: Natural deaths, used for research and educating clinicians.
Forensic (Medicolegal) Autopsies: Cover a wide range of non-natural deaths; perform external, internal examinations, and legal documentation.
Differences outlined include consent requirements, jurisdiction, circumstances surrounding the deaths, and retention of evidence.
Lecture 3: Basics of Crime Scene Investigation Protocol
Influential Figures and Concepts:
Sir Arthur Conan Doyle popularized scientific crime detection.
Mathieu Orfila: Father of forensic toxicology.
Alphonse Bertillon: Established the first scientific identification system (anthropometry).
Francis Galton: Developed fingerprinting methodology.
Leone Lattes: Created procedures for determining blood group of dried blood stains.
Calvin Goddard: Utilized comparison microscope for bullet analysis.
Albert Osborn: Fundamental principles of document examination.
Walter McCrone: Employed microscope for evidence analysis.
Hans Gross: First to describe the application of scientific disciplines in investigations.
Edmond Locard: Developed Locard's Exchange Principle, asserting every criminal connects to a crime through trace evidence.
Forensic Units:
Physical Science Unit: Identifies evidence via chemistry, physics, and geology.
Biology Unit: DNA profiling, hair and fiber comparisons, botanical material examination.
Firearms Unit: Analyzes firearms, bullets, and ammunition.
Document Examination Unit: Examines handwriting, ink, and burned documents.
Photography Unit: Records physical evidence through specialized imaging.
Toxicology Unit: Assesses bodily fluids and organs for drugs and poisons.
Polygraph Unit: Uses lie detection methods.
Voiceprint Analysis Unit: Examines audio evidence for suspect identification.
Evidence Collection Unit: Collects and preserves evidence from the crime scene.
Legal Challenges and Standards:
Frye v. US: Validity of lie detectors questioned; requires acceptance within the scientific community.
Daubert v. Merrill Dow: Judges as gatekeepers for scientific evidence admission.
Kumho Tire v. Carmichael: Gatekeeping applies to all expert testimony.
Expert Witness: An individual with specialized knowledge relevant to trials, providing scientifically grounded opinions.
Lecture 4: Fingerprinting
Fingerprint Database:
Over 200 million records in FBI database.
Friction-Ridge Skin:
Unique layer of skin on palms and feet.
Begins to form in human fetuses during third and fourth months of gestation.
Friction ridges are raised apertures around pores that join to form unique patterns; contain pores for eccrine glands.
Scarring varies based on dermal and epidermal damage.
Fingerprint Classification Types:
Pattern classification: Recognizes patterns, including types of arches, loops, and whorls.
Individual classification: Specific characteristics and minutiae unique to individuals.
Types of patterns include:
Plain arch: Ridges emerge on one side and flow to the other, valley in center.
Tented arch: Ridges enter like an arch but with an angle at center.
Loop: Ridges enter, curve, and exit the same side.
Whorl: Ridges make a complete circuit with two deltas.
Central pocket loop: One recurving ridge; no associated recurving ridge within pattern area.
Lateral pocket loop: Recurving ridge in a pocket formation with one delta.
Twinned loop: Includes two separate loop formations.
Accidental: Contains multiple patterns or none of the defined types.
Fingerprint Characteristics (Minutiae):
Types include ending ridge, bifurcation, and dot.
Temporary scars have sharp edges; permanent scars appear curled and puckered.
Types of Impressions:
Patent impressions: Visible prints created by substances on fingers.
Latent impressions: Invisible prints left via perspiration; can be transferred to various surfaces.
Methods of Recovery:
Powders: Useful for dry, smooth surfaces; fluorescent powders offer advantages.
Chemical processes: Various methods (e.g., cyanoacrylate fuming, iodine fuming) to develop latent prints.
Fingerprint Identification:
Manual comparison: Traditional practice.
AFIS: Automated Fingerprint Identification System for digital storage and searching.
LiveScan: Digitized fingerprint capturing.
Lecture 5: Blood Stain Pattern Analysis
Information Gathered from Bloodstains:
Origin, type of instrument used, direction of attack, relative positions during attack, number of injuries, and the truthfulness of accounts from witnesses.
Characteristics of Blood:
Cohesive nature leads to surface tension forming spheroid drops, which break upon impact—typically a volume of 0.05 ml per drop.
Blood droplets shape influenced by angle, size, surface type, and impact energy required to break surface tension.
Types of Bloodstains:
Passive bloodstains: Result from gravity; gather in low areas.
Gushing blood travels further than oozing blood.
Right-angle hits yield circular, while angled impacts create elongated stains pointing in the droplet's travel direction.
Projected blood splatters: Caused by applied forces (e.g., gunshot, heartbeats, external impacts).
Splatters classified by mechanism:
Stabbings, beatings, gunshots, arterial bleeding, expirated blood.
Impact dynamics analyzed:
Point of convergence: 2D representation where lines of blood trails meet; indicates area of origin.
Point of origin: 3D analysis of angle and position indicating the spatial location of the blood source.
Void patterns: Areas without blood indicating the attacker's location.
Spatter Classifications by Velocity:
Low-velocity: Occurs under 5 ft/s; large drops (>4mm); intuitively produced by dripping or arterial bleeding.
Medium-velocity: 5-100 ft/s; smaller patterns (1-4mm) from blunt/sharp impacts.
High-velocity: >100 ft/s; fine, mist-like droplets associated with gunshot wounds.
Transfer patterns: Result from contact between soaked and unstained objects (e.g., bloody handprints).
Lecture 6: Photography
Forensic Photography: Specialized field to preserve accurate representation of forensic evidence.
Accurate photographs required for judicial processes; they must represent the scene correctly and fairly.
Key Considerations:
Photographic authenticity depends on proper protocols and testimony; created images must not misrepresent facts.
Emphasizes quality over quantity in evidential images.
Redefining Perspectives:
Linear perspective crucial for spatial representation; it should match real-world conditions to maintain size perception accuracy.
Types of Scales for Evidence Photography:
Must be placed on the same plane as the evidence to provide accurate size indications.
Categories include size, color, and positional scales (e.g., GPS landmarks).
Photographic Documentation:
Essential for legal records; should include location and date relevant to the photography session.
Unenhanced photographs preferred; it’s critical to capture evidence detail accurately
Final considerations include authenticating digital photographs and adhering to documented practices to ensure the integrity of the images.