Forensic Anthropology Internship Series Ep.6: Forensic Concerns Behind the Bodies..

In this morning meeting, other than the five cases listed on the sheet, one extra case came in (if you do not understand what meeting or what is the sheet I am referring to, you may want to skim through this post first). It was a male that found in a canal.

According to the death/ medical investigator, he is a native American, and the family requested no autopsy due to their (religious) belief. The M.E. suggested doing an external autopsy and documentation of the body. This is the first time I encounter and realize pathologists’ hand could be tied not only because of family requests, but also jurisdiction.

According to American Indian Law, the Native Americans have their own police and they have jurisdiction on every member of the reservation, regardless they are indeed inside or out of the reservation.

While doing the external, the first thing the M.E. pointed out is the foam the coming out from the deceased mouth, which indeed is a mix of body fluids, and blood. This is always the sign of drowning as water has entered the thoracic cavity. Also the purplish color of the deceased face that stopped at his clavicles (the collar bones) is also a sign of drowning. Since the pathologist cannot open up the body, the M.E. only can examine him via external traumas. He suspects that is a blunt force trauma by touching the deceased’s head, as well as there are wounds on both interior parietal bones. A theory has it that he might be unconscious after his car hit on an object, and also because he was not wearing a seat belt, he was possibly then fell into a canal after that. That’s pretty much the info we could get from an external autopsy. The body was claimed by the Reservation jurisdiction later that afternoon.

On top of that, there was one decomposing body for autopsy today. According to the police, it is in its “advanced stage of decomposition”. According to forensic anthropologists, bodies that undergo advanced stage of decomposition should be “sagging of flesh; caving of abdominal cavity; loss of internal organs; extensive maggot activity; mummification of outer tissue; less than half of the skeleton exposed; adipocere may be present.” (Byers 100)  This stage suggests partial skeletonization and not much soft tissues on the remains. Yet, the body was in fact only in its primary decomposition stage OR just passed the primary decomposition stage and entering the advanced decomposition stage at most. (According to Byers (100), primary composition stage requires “some flesh relatively fresh; decoloration can vary from gray to green or brown to black; some skin slippage and hair loss; body bloated or deflated; skin may have leathery appearance.”) This is the first time for me to encounter the differences of classifications between the legal forces and pathologists/ anthropologists.

Though I remembered that my professor mentioned once in my forensic class, I never knew that there would be such a difference. This kind of makes you wonder what can be done to make the whole observation process or the examination process more in line with each law enforcement agents, in order to speed up the investigation.

Previous Episodes:

Forensic Anthropology Internship Series : Prelude

Forensic Anthropology Internship Series Ep.1: Getting to the Bones…

Forensic Anthropology Internship Series Ep.2: Two Lives in One Body…

Forensic Anthropology Internship Series Ep.3: Bone Donation

Forensic Anthropology Internship Series Ep.4: Two Cases (and bone overgrown on the skull)

Forensic Anthropology Internship Series Ep.5: Gunshot and Projectile Trauma

Resources:

American Indian Law

Byers, Steven N.. (2011). Introduction to Forensic Anthropology. 4th edition. Upper Saddle River: Prentice Hall, pp. 100.

Forensic Anthropology Internship Series Ep.5: Gunshot and Projectile Trauma

Trauma affects the skeleton via fracturing and dislocating the bones, which would disrupt the blood and nerve supply. Studying the osteological trauma can possibly tell the violence happened. There are three types of fractures: traumatic fracture, pathologic fracture, and periprosthetic fracture. Among these, we are going to discuss traumatic fracture, particularly from projectile trauma here with reference to the real case I encountered in the morgue.

The deceased was a male, in late twenties or early thirties. He expired at 6 am and two hours later, he is with us in the morgue. According to the death investigator back from the crime scene, he attempted to kill his girlfriend and suicide. His girlfriend survived, but not him.

Externally, there is one bullet hole on each side of the skull. According to the external condition, it is possible that the wound on the right would be the entrance wound, and the left would be the exit wound. Yet, it is the otherwise when we have shaved his hair and opened up the skull.

After shaving his hair however, the beveling is really clear. Judging from the projectile fracture and the beveling, the exit wound would be on the right and the entrance would be the wound on the left.

Trajectory of the projectile, usually gunshot wounds, can be located and identified as either penetrating when no exit wound is found, or perforating that a projectile has an entrance and exit like the captioned case. Crime investigation unit will usually use color stick to link the trajectory for verification. Speaking of beveling, a skull contains layers—inner and out table. The force of the projectile would impact differently on the layers, and caused differences performances on entrance and exit spot. Generally speaking, when a bullet enters it produces a sharp-edged on the outer surface of the skull, but “beveled-out” on the inner surface, and this is called internal beveling.

Internal beveling (Source: the University of Tennessee, Department of Anthropology)

External beveling is usually seen on the exit wound—the outer surface beveled out.  Yet occasionally would also be seen on the entrance site, depends on the way of holding the projectile and the distance of the projectile from the head. There is also one condition called the keyhole, which would only be seen when the entrance and exit wound overlapped.

External beveling (Source: the University of Tennessee, Department of Anthropology)

Keyhole wound (Source: the University of Tennessee, Department of Anthropology)

So, the entrance wound for this case is on the left and the exit on the right, does it mean the deceased is left-handed? According to the M.E., he stated that there are indeed studies done and show that no relevance with hand preferences to pull the trigger.

The M.E. also pointed out that sometimes blunt force and projectile force trauma may not directly fatal. The energy from the trauma could be transmitted and make the brain tissue hit on the foramen magnum that creates a second wave of trauma. That would delay the death a little.

Also, on the other case that another M.E. was working on, they found negative results from autopsies on cause of death. They found only hemorrhage in his brain but the skull did not fracture at all. He decided to open up the deceased at the back and see if they can trace fractures, possibly compression fracture on the neck and the spine that would cause instant death, and the autopsy later confirmed this manner of death.

Tik-Tok: Estimating the time has elapsed since the death…

We are all dead.

We have exhaled the last breath. Our heart has stopped pumping blood for the brain and the body. We died.

Unfortunately, no one was with us when that moment came until now. Will the coroner and the medical examiner know when that particular moment happened? Yes.

How? They have the interval detectives.

Upon the discovery of human remains, the key question asked usually was the time of death. To answer that question, M.E. has to find out the postmortem interval (PMI), which is the amount of time has elapsed since the death.

Photo illustration by James Emmerman. Photo by Shutterstock

There are ways to do so. Recalling the decomposition schedule we discussed last time, in the first few hours, a lot of changes would happen: livor mortis (settling blood, algor mortis (cooling of body temp) and rigor mortis (stiffness). These methods usually able to accurately calculate the first, at most 24 hours interval. By the time the body starts decomposing, these would not work.

A lot of Medical Examiner would choose to use the drop of body temperature as a tool to get PMI. Average body (living body) temperature is about 37⁰C or 98.6⁰F. Under normal circumstances, at normal room temperature, the body would drop 1.5⁰C in the first hour after death, and between 1.5 and 1⁰C every hour after that, and stopped until it reached the room temperature. By comparing and calculating, it would allow the M.E. find the time of death. Yet, it does not work at best when the body starts decomposing.

A number of factors will affect the rate of the temperature drop. A naked body will be at a faster rate than a body that is wrapped like a gift. Also, body of lesser weight will enjoy the privilege of faster temperature drop too! If the body has been dead for days, looking into the past weather reports would help too.

Seems like everything does not work as well when the decomposition begins. Correct! But we are so lucky that the mother nature gives us our little death detectives– insects!

The application of insects or bugs science to investigation about crimes is called forensic entomology. Entomology, means the study of insects. The live and dead insects found at the site of crime can tell many things, from the crime scene, the length of time the body had been there, the time since death, and even if the victim being drugged.

After the rigor mortis is over, putrefaction begins. It is about the internal breaking down of the proteins in a decomp body. Acid like the gastric juice (Hydrochloric acid) starts eating the internal organ, releases gases (ammonia, nitrogen, carbon dioxide, and methane). They sometimes bloats the body cavity. As the decomposition goes, the odor would get stronger. That’s the odor cadaver dogs rely on to look for a body. Lately, an international research team measured the volatile organic compounds (VOCs) from pig carcasses, they identified a cocktail of several families of molecules. The found that the combination and quantities of the VOCs change as the body go through stages of decomposition. It worked as the “odor fingerprint” of decomp.

Insects then, particularly flies, begin feeding on remains. Studies show that flies are attracted by the released gas, and have a feast around the moist and opened tissues/ areas: eyes, ears, nose, mouth, vagina, penis, anus. If there are wounds (antemortem and perimortem), they would invite themselves into these areas too. As they continue to enjoy the feast, they reproduce. The deposit eggs in and around the remains, and starts a cycle of arthropod activity. The schedule is as follows (Bass 1977):

  • First Day:  Egg masses of insects (may look like white sawdust); veins seen through skin may be blue or dark green; body fluid may be present around nose and mouth.
  • First Week: Maggots are active on the face; bones around eyes and nose may be exposed; beetles may appear; skin and hair may slip from the body; remains emanate odor of decay; abdomen may be bloated; molds may begin appear on the skin; animals may be active. VOCs or Volatile fatty acids may killed the vegetation in area around the body.
  • First Month: Maggot activity less, beetles more common; no more bloating. Bones will be expose if the body is shaded. Skin may be leathery if its exposed to sunlight, which protects the maggots from the sun. Mammalian carnivores may appear and remove body parts; molds can be found; adipocere (Grave Wax) may be present.
  • First Year: Skeleton fully exposed and bleached; moss and/or green algae may be growing on shaded bones. rodent gnawing; animals may nest in the skull.
  • First decade: Exfoliation of cortical bone may be present; longitudinal cracks may occur in long bones exposed to sun; roots of plants may be growing in or through bones.

“You are what you eat. So do the insects.”

As you may realize by now, the insects are entirely fed on the body. Entomologist by studying the living habit or the life cycle of the insects may be able to tell if the insects have intake some alternative materials from the body, such as necrotic. Likewise, insects can help clean the bones by having them eating up the soft tissue. These are the most convenient way to do if maceration is not on the top of your list.

Other than forensic entomology, forensic botany (the application of plant science to investigation about crimes) is also useful to map out the time elapsed since death. You may recognize in the above schedule, the plant would die out after the first week. The acids from the internal body would kill all the nutrients, acidify the soil, and make the soil is not suitable for plantation. However, later on, when the whole body started breaking down, the whole body is indeed some sort of organic nutrients. The decomposition of body thus can restore the nutrients into the acidify soil. Plants will grow nice and strong at the spot. Thus, abnormal plantation patterns may reflect the placement of dead body too. Plus, plants and roots would grow around the bones (as support sometimes).

A new finding from Forensic Biologist from Switzerland found that the density of testate amoebas in the soil underneath the cadavers help date older corps. The study finds that not one single living amoeba found be found under the cadavers at 22 and 33 days after placement, while only by day 64 the amoebas start to rebound in the soil under the pig. Yet, the level of amoebas did not restore to its normal level (according to the control) even after a year.

References:

Bass, W.M. (1997). Outdoor decomposition rates in Tennessee. In: Halgund, W.D., Sorg, M.H., eds. Forensic Taphonomy. New York: CRC Press.

Byers, Steven N.. (2011). Introduction to Forensic Anthropology. 4th edition. Upper Saddle River: Prentice Hall, pp. 94-111.

Frazer, Jennifer. (2014). “A Surprising Time-of-Death Tool.” Scientific American. September 16, 2014.

Knowles, Ruth. (2014). “Changing Smell of Corpses Measures Time of Death.” Scientific American. June 26, 2014.