Forensic Science 1- Death Investigations-University of Southern Mississippi

Scene Investigation

The preliminary reconstruction of events before death; all significant scene details must be recorded.

Blood, Tire, and Fingerprint Documentation

Blood spatter/flow, tire marks, shoe prints, and fingerprints must be documented, processed, and collected.

Evidence Collection at Scene

Collect all discarded or cast-off items, weapons, bullets, and casings; photograph before altering the scene.

Autopsy (Definition)

Examination of a body after death (postmortem) to determine cause and manner of death and assist criminal cases.

Evidence from the Autopsy

Examiner evaluates body; retains tissues/organs for pathology or toxicology; coordinates with investigators for evidence.

Evidence Commonly Collected at Autopsy

Clothing, fingernail scrapings, hair combings, buccal swab, sex-crime swabs, bullets, gunshot residue, and DNA swabs.

External Examination

Broad overview of body and clothing; classify injuries such as stab vs. gunshot wounds.

Internal Examination

Removal of organs via Y-shaped incision; organs are weighed, dissected, and sectioned.

Toxicology Samples

Taken during internal exam—blood (alcohol/drugs), stomach contents, bile, urine, vitreous fluid.

Cause of Death (Definition)

The event, injury, or disease initiating the chain of events resulting in death.

Common Causes of Death

Blunt-force injury, sharp-force injury, asphyxia, gunshot wound, and substance abuse.

Blunt-Force Injury

Injury by non-sharp object (bat, pipe); includes abrasions, contusions, and lacerations.

Abrasion

Superficial injury caused by rubbing away of skin; may be patterned.

Contusion

Bruising from ruptured blood vessels beneath the skin.

Laceration

Splitting, tearing, or shearing of tissue due to blunt impact.

Sharp-Force Injury

Wounds from knives or blades; cuts or stabs; defensive wounds may be present.

Asphyxia

Interference with oxygen intake—includes hanging, strangulation, or carbon monoxide poisoning.

Gunshot Wound

Projectile injury; pathologist determines trajectory and shooting distance.

Substance Abuse Deaths

Common cause; toxicology tests ordered; may show foam, vomit, or drug paraphernalia.

Manner of Death (Definition)

Circumstances leading to death; classified into five categories.

Five Manners of Death

Homicide, suicide, accidental, natural, and undetermined.

Algor Mortis

Body cooling after death; loses 1-1.5°F per hour until matching ambient temperature (varies by conditions).

Livor Mortis

Blood settles in lowest areas; begins 20 min-3 hrs after death and fixes within 16 hrs; movement changes patterns.

Rigor Mortis

Muscles stiffen 0-24 hrs after death and disappear within 36 hrs.

Vitreous Potassium Test

Measures potassium levels in eye fluid to estimate time of death.

Stomach Contents

Examined to estimate last meal and approximate time of death.

Decomposition

Advanced decay where earlier postmortem indicators (algor/livor/rigor) no longer apply.

Recovering and Processing Remains

Treat recovery sites as crime scenes; secure area; document bones, impressions, and all evidence.

Forensic Anthropology (Definition)

Identification and analysis of human skeletal remains to determine sex, age, race, and injury.

Determining Sex from Skeleton

Based on pelvis and skull features—female pelvis is wider; male skull larger with pronounced brow.

Estimating Height from Skeleton

Calculated using long bones.

Estimating Age from Skeleton

Based on bone fusion, structure changes, and dental development.

Facial Reconstruction

Technique used by forensic anthropologists to identify skeletal remains visually.

Forensic Entomology (Definition)

Study of insects related to criminal investigations; helps estimate postmortem interval (PMI).

Blowfly Importance

Most common species for PMI; bright green/blue; life cycle from egg to maggot to adult helps estimate death time.

Fly Egg and Larvae Development

Maggots feed on human tissue; development stage indicates how long a body was exposed.

Environmental Influence on Insect Evidence

Temperature, location, climate, and drugs affect insect growth and PMI accuracy.

Collecting Insect Evidence

Done by entomology expert; includes temperature readings and specimen collection from all body areas.