ENTOMOLOGY (and the roll it plays) PART 2

In my previous post about entomology I explained a little about how conditions and location of the scene and body can affect how quickly (or slowly) insects can show up and begin to lay eggs on a corpse. I also provided photographic examples of the growth rates as observed in my own experiments.

In this post I will talk more about how forensic entomology can be helpful in a death investigation.  As I am not an entomologist nor have I worked in a lab, I consulted some of my training resource materials for this post.

Flies are normally the first to arrive and will usually lay their eggs in warm, moist areas so the larvae can feed on the softer tissues. This can include the obvious, such as the eyes, ears, nostrils, and if accessible, the genitals.  If there are anomalies on the body such as open injuries whether associated with the death or pre-death medical wounds, the flies will also be attracted to those areas as well.




When there is no information regarding the death, especially in a suspicious death, law enforcement may decide to collect the insects present both on the body and around it. Most crime scene investigators are now being trained in collection.  The collected specimens can provide quite a bit of information if properly handled and a knowledgeable entomologist is consulted for species type and origin.

One of the main pieces of information that forensic entomology can provide is a time frame.  Insects usually arrive in a fairly predictable order, with (as stated above) flies usually being the first on scene.  The temperature will greatly affect the rate of decomposition and changes in the body as well as the growth rate of the arriving insects. If it is an outdoor scene, weather can play a factor in which insects arrive. It is important to research the recent as well as present weather and temperatures.  Investigators at an indoor scene should note the settings on the thermostat at the time the body is found.  In a suspicious death, it is not uncommon to find the inside thermostat has been set at an unreasonable setting – such as the heater turned up to speed up decomposition or the air conditioner set very low to keep the body cold and slow down the rate of decomposition.  These variations on the inside temperature can affect insects being attracted to the scene, especially if it is exceptionally warm inside and cooler or damp outside.

When a body is found days to weeks after death, it is important to search for pupa.  If the body is on a bed or carpet, they can often be found under the body or bedding.  However, when the body is unclothed and on tile, it can be a little harder to find them.

CASE EXAMPLE: I once had a case of a body who had died in a chair, she was wearing only underwear and the room she was in had a tiled floor.  It had been well over a week since she was last known to be alive. It was summer time and warm inside the house, even with air conditioning (which was set at an appropriate setting). She was in a severe state of decomposition, with body fluids on the floor around her and running along the grout of the tiles.  I could see damage to her tissues from insects, including maggots.  I had to study the floor closely to distinguish the tracks left by the migrating larvae.  I actually found the hiding and transforming pupa across the room near the front door, under several plastic bags from a local store. In addition, the purchased items were still in the bags, along with the receipt. This additional information corresponded with the time frame of last known alive. It serves to show that when investigating a scene, never be too quick to rule out or ignore information that might be right in front of you!!!

Observing the growth rate of the insects present, the weather and climate of the scene (whether inside or outside) and the activity noted on the body can combined provide a good estimate of when death occurred.



In addition to helping estimate the time of death, forensic entomology specimens can often tell us other important information.  If there is blood evidence elsewhere than the body, the flies will often be attracted to those areas as well, which can be very helpful if those spots would not be easily visible otherwise. If maggots who are feeding on the body are collected and tested, they can often yield toxins and drugs that were in the body at the time of death.  If the body was left somewhere for hours or longer, then transported a distance and/or buried, then the eggs, larvae or insects on the body might tell investigators where the body had originally been.  If a vehicle is suspected as having transported a body (or been involved in another crime), then forensic technicians can collect insects off the front and undercarriage of the vehicle to help determine where the vehicle had travelled.  DNA technology is advancing quickly and will surely at some point include testing of larvae collected on a body for body fluids and DNA.

Unfortunately, there can some issues with insects.  They can create a false positive for blood by walking through the decedent’s blood, then fly to the wall and walk around the wall leaving small dots of blood. This can also confuse blood patterns to the untrained eye. There are many other insects and creatures who are not interested in feeding on the body but instead prey on the eggs and larvae.  Ants, wasps and beetles are just a few of the critters who come to feed on the larvae. Ants can create areas that appear to be injuries, when they are actually what we call “artifact” and must be noted as such.

In Tennessee, there is a research facility named The Body Farm.  At the facility they place donated bodies in many different situations to study decomposition and forensic entomology.  You can get to the website with this link    http://www.jeffersonbass.com/tour-the-body-farm.html

Please note there are real human bodies in the photos presented on the link.

Even an old dog like me can learn something new! While watching a true crime show on the ID channel I learned of a new way DNA is being used to help law enforcement get an idea of what their suspect might look like.  To read about the technique follow this link to the Parabon Nanolabs.    https://snapshot.parabon-nanolabs.com/



Entomology PART ONE 

(P2 will discuss how entomology is used in death investigations)

When a body dies, human or animal, it begins to decompose.  In the beginning it can be very difficult to see any signs of decomposition.  Of course, just as with other situations, the scene (inside or outside, temperature, etc) play a very big factor in how quickly decomposition begins to happen. However, insects and animals have such a hyper sense of smell, they seem to know within minutes.  Flies show up very quickly and are usually the first to arrive.  Obviously, if a person dies in a clean house, with no open windows or doors where flies have access to enter, then the flies are delayed.  If there is someone else in the house and the authorities are notified quickly, then it is unlikely flies will have access to the body.

In a different scenario, such as a house in which the person is alone, and has an open window which does not have a screen, or an open slider without a screen, then flies have quick and easy access.  In a short amount of time, flies will enter and explore the body.  If the body is dressed or perhaps covered in bed where mostly the neck and face are the only areas easily accessible. If the body is uninjured, then the flies will go to the eyes, nose and mouth and occasionally the ears.  They will find a warm, moist place and lay their eggs.

If the body is inside, completely naked and the flies have access to come inside they will go for they usual eyes, nose and mouth, but they will also go for any other warm moist areas they can access.  If the house is in bad shape, such as a hoarder house, there will also be ants, cockroaches and rodents already in the house which will also investigate the body but will be interested in it as a food source more than to lay eggs.  Ants often leave tracks of little bite marks which can often be wrongly thought to be abrasions or scratches. Because the person is dead when the ants bite, there is no swelling or inflammatory response.

If the body is outside, then the flies and other local insects will come right away.  The hotter the temperature the faster the eggs laid by the flies will mature.  If there are any wounds, the flies will concentrate there as well as the usual places I mentioned previously.

There are so many variables when using forensic entomology to make determinations in the investigation.  It is very important to photograph the body with the insects in place before collecting specimens.  Then carefully log them as you collect.  One area at a time, collect live specimens as well as  specimens to be preserved at their current stage. Log and photograph as you go as well as labeling each collection container.

In order to better understand the daily growth patterns, I grew maggots in my yard with a controlled environment. I photographed and documented daily.  I used animal liver that I obtained from the market and did not disrespect any persons in order to carry out my experiment.

The following photos are from my experiments from growing fly maggots at my residence.


You can see flies on the fresh specimen as they lay eggs.



Eggs in their early stage. Can usually be seen in 24 hours or so. They are usually laid in a mass, as you can see in the lower right of the photo.





This is a piece of the liver after the maggots have been feeding off of it.  You can see it is desiccated or dried out.


Through the photos you can see the maggots changing as they grow. When they are ready to change they crawl under something or into the dirt and their outer layer becomes a hardened shell.  This is called the Pupa stage.


The flies emerge in about 2 weeks depending on the weather and conditions of their surroundings. In the photo above you can see a green bottle fly and a gold bottle fly that emerged from the casings.


Some of the tools I keep in my collection kit.

In part 2, I will discuss how entomology can be used in death investigations.



DECOMPOSITION is the process of the body breaking down and decaying. This starts as soon as death occurs however it is not immediately visible. There are many factors in decomposition and the rate at which is occurs.  The location of the body is one main factor – is it inside or outside.  The temperature of the location is another big factor.  The hotter the location the faster the body will decompose.  The condition of the body is another factor. Whether the body muscular or obese will be a factor as fat will decompose at a different rate than muscle.   If the person/body is sick or damaged in some way in which air, moisture or insects (covered in the next post) will reach the organs faster than normal, can speed up the process.

This are screen shots from my teaching powerpoint,  It shows some of the variations of decomposition.

description of decompdecomp pic3deomp pic1

The majority of these photos were taken of decomposed bodies inside residences.  The one with the foot labeled “desiccation”  was of a body that had been inside a warm residence for at least 2 months before being found and was essentially closer to being mummified.  This is what you would normally see of remains left outside in the heat for a long period of time.

The Mortis Brothers. Who??? (What!)

The Mortis Brothers  

Rigor Mortis, Algor Mortis and Livor Mortis – sometimes referred to as the “Mortis Brothers”

Rigor Mortis

Rigor Mortis is due to a biochemical change in the muscles that occurs several hours after death, though the time of its onset after death depends on the ambient temperature.

  • Within ½ to 1 hour = becomes apparent

  • Approx 12 hours = increases to max

  • Approx 12 hours = set / stays

  • Approx 12 hours = decreases / relaxes

  • Once fully established, the breaking of rigor in joints is irreversible and it will not reappear.

  • Rigor mortis appearance and disappearance is accelerated by prior exercise, convulsions, electrocution or hot environmental temperature. In a hot environment, for example, the rigor mortis may disappear in only nine to twelve hours.

Algor Mortis

Under average conditions, the body cools at a rate of 2.0 F to 2.5 F per hour during the first hours, and slower thereafter, with an average loss of 1.5 F to 2 F during the first twelve hours, and 1 F for the next twelve to eighteen hours.

Livor Mortis aka Lividity

  • Postmortem Lividity or postmortem hypostasis is a purplish-blue discoloration due to the settling of blood by gravitational forces within dilated, toneless capillaries of the deceased’s skin.

  • Blood loss and/or anemia can cause difficulty in discerning Lividity.

  • In individuals with dark skin pigmentation, Lividity in the skin can go unnoticed.

  • In early stages, livor can be blanched by compression.

  • In certain cases, it may be difficult to distinguish between postmortem livor and ante mortem bruises. Incision of the skin may be required.

There are many factors that affect rigor mortis, so the times listed above are only averaged guidelines.  Whether a person is obese or thin and muscular play a big factor since rigor occurs in the muscles, and certain disease processes can alter the time as well.  We use stages of rigor to help determine if the story we are told, as well as the scene, fits with the way we find rigor to be. For example, if we are told someone was speaking just before death, but they are stiff with rigor, we know the story is not accurate.  Another example would be if the rigor was not consistent with the position the person is now observed. We cannot pin point a time of death from rigor mortis. We can only determine if it is consistent with the time frame and story we are told.

rigor-mortis1  ziff rigor

Algor Mortis

Under average conditions, the body cools at a rate of 2.0 F to 2.5 F per hour during the first hours, and slower thereafter, with an average loss of 1.5 F to 2 F during the first twelve hours, and 1 F for the next twelve to eighteen hours. As with rigor mortis, algor mortis times are a guideline and not exact.  A person’s condition (such as body fat or disease) can play a part in how quickly – or slowly – their temperature drops. If they are on a pillow top mattress they will stay warmer longer because the pillow top retains body heat.  If they are inside but near an open window and with cold air blowing in, they will cool down faster. If we know someone has been deceased for awhile – such as several hours – but they are outside and their temperature is still very high, and especially if it is higher than normal, then we must consider heat exposure as a factor in their death. This can occur inside too, when someone does not have adequate temperature regulation and it is very hot outside. If it is very cold, and the decedent is inadequately dressed or outside, then we use their temperature to help determine if exposure to the cold could be a factor in their death.

Livor Mortis or Lividity.

Postmortem Lividity or postmortem hypostasis is a purplish-blue discoloration due to the settling of blood by gravitational forces within dilated, toneless capillaries of the deceased’s skin.

Blood loss and/or anemia can cause difficulty in discerning Lividity.  In individuals with dark skin pigmentation, Lividity in the skin can go unnoticed.  In early stages, livor can be blanched by compression.  In certain cases, it may be difficult to distinguish between postmortem livor and ante mortem bruises.  Incision of the skin may be required.

Lividity is often mistaken for bruising by the untrained. One of the ways we check lividity, is by applying moderate pressure with a finger.  If the pressure is able to change the color to white, we consider that “blanching” and lividity is NOT set.  If the coloring does not change, then we consider the lividity “set” or “fixed.” (see pic)


Occasionally we will see some lividity on both the anterior (front) and posterior (back) of the body.  This indicates the body had been in a position for awhile, then moved to another position. If we are told the decedent was NOT moved, then our findings contradict the story. This is important, however it is not unusual for someone to find their loved one face down and roll them over when they don’t respond. If they admit this up front, then mixed lividity would not be as surprising.  Lividity can often tell us where the person had been laying. See the photo inserted.  You can see where the decedent had been lying on a flat service causing part of their back to not have lividity.

lividity 2

In an investigation, we use each finding as part of the puzzle of what happened.  By checking many different factors, we can discover if there is something that does not fit with the story and/or the other findings. This helps us determine if there is something suspicious in what might otherwise appear to be a nature or non-criminal death.


Time of death



Establishing time of death is often more complicated than they make it seem on television.  The following information is based on California laws regarding death certificate criteria.

Determining TOD in an unwitnessed death is almost impossible to do.  There are times when someone dies alone or “unwitnessed” and there is something that can help us narrow down the approximate time the person died, such as a gunshot being heard, or the dying person being on the phone with someone when they stop breathing, or an event that caused an immediately fatal injury such as a traffic accident, explosion, a lightning strike and other similar events.  For example, there was a case handled by my office in which someone was attempting to steal copper wiring from a metal control box. When they attempted to cut the wire, they were electrocuted and actually caught fire. Although the event was not witnessed, there was a loss of power to a small area and the time of the power loss was recorded by the company as well as the people who lost power.  In that instance we can have a pretty good idea what time death occurred because it would have been instantaneous due to the amount of electricity.  There have also been many time a traffic accident is heard, and when first responders arrive one or more of the victims are already deceased and their injury is one that would be immediately fatal such as extreme crushing injuries to the head and chest. One issue with time of death is the person has to be officially pronounced dead by someone qualified to do so. This is usually a first responder such as a paramedic, or law enforcement official. In hospital deaths, it is usually a physician, or a nurse at the direction of a physician.  In many cases, the time of death (TOD) is the pronouncement time as recorded by the physician or first responder.

However, in unwitnessed cases, we often use the term FOUND TIME instead of TIME OF DEATH.  The reason for this is we do not know the actual time of death.  We take the time the first responder arrived and confirmed the person was deceased. We then determine when the decedent was last known to be alive.  If it was not on the same day they were found, we will list a FOUND DATE, then list the pronouncement time listed in the TOD space. This basically certifies we cannot establish the exact time of death but only when the person was found.  In our investigative report we will elaborate more about the last time known alive, and how long the physical findings indicate the person was probably deceased.  This is where temperatures, exposure, stages of rigor mortis and decomposition come into play.  I will discuss those topics in a later post….

A second area on the death certificate which is important in NON-NATURAL deaths, is the INJURY section. In some cases, the injury date and time is the same or very near the time of death, and in others it can be years apart. In an unwitnessed death this entry is often marked UNKNOWN. If a gunshot, traffic accident or other factor can provide the injury time we will use it.

Grief…. Is “Closure” possible??


CLOSURE….. I have come to dislike that word.  So many people use it.  You hear cops, doctors, family and television use that word. The family needs closure. I want closure.  If I just know who did it, or what happened, or if we just find the body, or if the suspect gets convicted…. THEN I/we/they will have closure. NO I say they won’t. Let me explain WHY I say this. To say someone will have closure at some point after the loss of a loved one indicates that the living will be able to say I got my answer and now I am done grieving and will move on. As someone who has lost many friends and family, including both of my parents, I don’t believe there is any answer a loved one can receive that will bring THAT much relief. I also, at least for myself, do not believe someone ever stops grieving.  We may reach a point in which we stop allowing our grief to control our life. We may reach a point where we are now able to get up, go out into the world and move forward but that does not mean we are done grieving.  My mother has been gone for over 10 years now, but I still miss her, and some days I truly grieve for her – and yet I am finally at a place I can go through boxes I packed up after she died, see memories, see things written in her handwriting, and once in rare instance come across an article of clothing that has been packed away in such form that I can still smell my mom’s perfume or more often her cigarettes, and it makes me smile sadly at the memory it invokes, but I no longer curl up in a fetal position and cry.

It is my personal and professional opinion that there is no set time for grieving. Is it possible to be locked in your grief to the point of it being unhealthy – of course, but I hate when someone tells a grieving person that it has been long enough and the need to “get over it”. Please do not criticize, or judge a person who is grieving. Do not ask them what will give them closure, because I believe there is no true “thing” for anyone that completely provides closure.

Grieving to little is just as bad. I say this because if you just shove those feelings deep into the back of your mind and force yourself to move on and not think about then someday, one day, I assure you – you will crack and shatter, and it will not be pretty.

When I would speak with families during the process of my investigations, I would tell them to take their time and do not be hard on themselves or on each other. Everyone grieves differently.  If you have lost more than one loved one, you will likely grieve differently with each. It also matters how you find out about the loss of your loved one.  For those of us (yes including me) have been the one to find your loved one dead from a traumatic event, such as suicide, homicide, decomposed, etc., it is even more traumatizing than being at the bedside in a hospital or being told after the fact. Once you see your loved one like that, you cannot flush the vision out of your mind. Eventually you can go days, weeks, maybe even months without thinking about it, but it will come and go and it will never go away completely.  I would always discourage and sometimes prevent family members who would come to the scene from seeing their loved one in a bad way. Working a job like mine made my grief harder to push past.

In closing I beg of you to please be supportive to those who grieve and if/when you (the reader) are grieving, please seek a support group or someone you trust if you need to talk about it.  Don’t keep it all inside and wait until you explode.  Do something that helps you. One thing I did was make a memorial garden for my parents. My husband made a beautiful wooden bench and I can sit and “visit” my parents anytime as they both have engraved granite urns that have been placed in the garden. My cousin had a star named after my mom.  There are little things you can do to honor and memorialize your loved ones.