ABMDI Medicolegal Death Investigation 2 — Questions and Answers
Question 1: Which postmortem change involves the settling of blood in dependent body areas due to gravity after circulation stops?
- Rigor mortis
- Livor mortis (Correct answer)
- Algor mortis
- Putrefaction
Correct answer: Livor mortis
Livor mortis (also called lividity or hypostasis) is the purplish discoloration caused by blood pooling in dependent tissues after the heart stops pumping.
Livor mortis begins within 1-2 hours of death and becomes fixed (non-blanchable) at approximately 8-12 hours. The pattern and distribution of livor can indicate body position at death, whether the body was moved, and approximate time since death. Fixed livor that conflicts with the current position suggests repositioning occurred after approximately 8 hours.
Question 2: An MDI arrives where the decedent is found face-down but lividity is fixed on the back. This finding most likely indicates:
- Death occurred in the face-down position
- The body was moved after lividity fixed (Correct answer)
- Lividity is unreliable in this case
- The decedent suffered a cardiac event
Correct answer: The body was moved after lividity fixed
When fixed lividity on the back is inconsistent with the face-down position, it indicates the body was repositioned after lividity became fixed, typically 8-12 hours post-death.
Fixed lividity that contradicts the current body position is a critical investigative finding suggesting homicide, concealment, or body movement. The investigator must document this discrepancy and communicate it to the medical examiner. It can significantly change the manner of death determination.
Question 3: What is the primary purpose of the chain of custody in a death investigation?
- To speed up evidence processing at the laboratory
- To ensure evidence integrity and admissibility in court (Correct answer)
- To assign responsibility for autopsy scheduling
- To limit access to the scene to law enforcement only
Correct answer: To ensure evidence integrity and admissibility in court
Chain of custody documents every person who handles evidence, ensuring its integrity is maintained and that it will be admissible in legal proceedings.
Chain of custody is a continuous legal record of the collection, transfer, storage, analysis, and disposal of evidence. Breaks in chain of custody can result in evidence being ruled inadmissible. MDIs must document the time, date, collector name, and condition of each item collected at a scene.
Question 4: During a scene investigation, the MDI observes maggot activity on the decedent. What is the primary investigative value of this finding?
- Confirms manner of death as homicide
- Assists in estimating postmortem interval (Correct answer)
- Indicates the exact cause of death
- Confirms the identity of the decedent
Correct answer: Assists in estimating postmortem interval
Forensic entomology uses insect activity including maggot species and development stage to estimate the postmortem interval (time since death).
A forensic entomologist can analyze insect specimens collected from the body to estimate the minimum postmortem interval. The blow fly (Calliphoridae) is typically the first insect to colonize remains. MDIs should collect maggot samples in alcohol and alive, note ambient and maggot mass temperatures, and photograph insect activity before disturbing the body.
Question 5: Which best describes the difference between cause of death and mechanism of death?
- They are interchangeable terms used on the death certificate
- Cause is the disease or injury; mechanism is the physiological derangement leading to death (Correct answer)
- Mechanism is listed on Part I of the death certificate; cause is listed on Part II
- Cause of death is determined by law enforcement; mechanism by the medical examiner
Correct answer: Cause is the disease or injury; mechanism is the physiological derangement leading to death
Cause of death is the disease or injury that initiated the fatal sequence; mechanism of death is the physiological abnormality (e.g., cardiac arrest) that directly caused death.
For example, the cause of death may be blunt force head trauma while the mechanism is cerebral herniation. Mechanism of death alone (e.g., cardiac arrest) should not be listed as a cause of death on the death certificate because it is nonspecific.
Question 6: When documenting a suspected unattended natural death, which action should the MDI perform first upon arrival at the scene?
- Collect biological samples from the decedent
- Ensure scene safety and confirm law enforcement has secured the area (Correct answer)
- Photograph the decedent before touching anything
- Contact the next of kin to notify them of the death
Correct answer: Ensure scene safety and confirm law enforcement has secured the area
Scene safety is always the MDI's first priority. The investigator must ensure the environment is safe and that law enforcement has secured the area before any investigation begins.
Before entering any scene, the MDI must assess for hazards (toxic substances, unstable structures, biological hazards, weapons). Law enforcement should have secured the perimeter. Only after safety is confirmed should the MDI begin the systematic scene investigation.
ABMDI Medicolegal Death Investigation 2
Which postmortem change involves the settling of blood in dependent body areas due to gravity after circulation stops?