Hyperspectral Imaging and Corpse Location

One of the most difficult things criminal investigators can face is locating a corpse that has been dumped in a remote location. Large number of searchers will fan out in any area where the body might be and spend many hours and days searching, often without result. Cadaver dogs can help in that they can detect the odor of decomposition, even in buried corpses. Arial infrared scanning can also be useful since a decomposing corpse tends to produce heat, which the scanner can detect against the cooler background of the surrounding soil. Also, aerial photography can help by indicating areas where the natural vegetation has changed in some way.

A decomposing corpse can initially produce a toxic environment for plant growth and can therefore make the vegetation less lush in that area. As the decomposition process progresses however it often serves as fertilizer and enriches plant growth so that they are greener, more lush, and appear different than the surrounding growth. Aerial photography can often detect this.

A new technique has been developed by scientists at McGill University. It is called Hyperspectral Imaging. It is similar to aerial photography but more sensitive. It also can be useful over a longer period of time.

Initially the chemicals of decay released by the body can inhibit plant growth and alter the way light is absorbed or reflected by the plants near the burial site. Early on they don’t reflect visible and infrared light as well but after several years they tend to reflect light much more readily. This new hyperspectral imaging system can detect these differences and therefore locate the burial site. Burial sites as old as 50 years have been detected using this technique. Exciting stuff and it will be interesting to see how this develops.

For more on locating and then identifying corpses check out my book Howdunnit: Forensics.

 

Hand-Held Sniffer and Body Location

So you’re bad guy has buried his victim somewhere on his vast farm. Your sleuth knows this but can’t prove it. Locating the corpse is critical to making the case. Search teams and cadaver dogs are brought in but the days drag by with no results.

Electronic noses were developed for this very circumstance. These devices are basically gas chromatographs. They sample air near the grave where the molecules of decomposition percolate up from the decaying corpse. Thomas Bruno, a physicist at the National Institute of Standards and Technology (NIST) recently reported in New Scientist the development of a handheld sniffer device, which should allow investigators to more quickly cover large areas, allowing for more timely corpse location.

I earlier posted a note about microfluidics. This device incorporates some of that technology. The device contains a very thin capillary tube whose inner surface is coated with aluminum oxide. Air is then sucked into the tube. If this air contains any of the various amines produced by decomposition, these molecules will combine with the aluminum oxide. This new amine-aluminum oxide combination can be detected using UV light.

This device is still in the developmental stage but could prove to be a very useful tool for corpse location.

 

Diatoms on Clothing and Corpse Location

Drowning is one of the most difficult causes of death for the medical examiner to determine. You would think he would simply have to find the lungs filled with water to make this call but that’s not the case. If a corpse is tossed into a body of water, the lungs will passively fill with water as the air escapes and is replaced with the liquid. So the simple finding of water-filled lungs does not prove the cause of death was drowning.

But the medical examiner has a couple of tricks that can sometimes help. Though not always present, if he finds debris within the mouth and lungs as well as damage to the nasopharynx and the airways, both of which result from the victim struggling for air but only breathing in water, these findings would suggest that the victim was alive when he entered the water. Debris deep within the lungs can’t get there passively and must be inhaled.

And in some cases, diatoms can help.

Diatoms are microscopic organisms that live in all types of water. They can be found in oceans, lakes, and your own bathtub or swimming pool. These tiny creatures are protected by a silicon–containing shell that is quite resistant to damage. They survive in a corpse for a long time. Though controversial, they can be used for determining if someone drowned. In this circumstance, as water is inhaled in the lungs, these diatoms worked their way from the air sacs of the lungs into the bloodstream and from there escape into the tissues, particularly the bone marrow. The medical examiner can test the bone marrow of a suspected drowning victim and if he sees a large number of diatoms then he might conclude that the victim died of drowning.

Now it seems that diatoms might also help locate where a crime took place in cases where the corpse has been moved and the victim’s clothing contacted water. A recent study in the journal Forensic Science International suggests that diatoms can be found in the victim’s clothing. Cotton clothing that has contacted water will absorb and retain the diatoms from that water. If these can be located and identified then they can often be traced back to the source. Diatoms vary from location to location so comparing those found on the victim’s clothing with those of a certain location might be useful in placing the body at that location.

This can be very useful to investigators when a person has been killed near a body of water and then their corpse is dumped at another location. Locating the primary crime scene–the place where the murder took place–is extremely important to investigators since this often results in finding further evidence that leads to the perpetrator. If these diatoms can help make that connection, they might prove to be a useful investigative tool.

 

On This Day: King Tut Found

On this date in 1922, Howard Carter discovered the entrance to the tomb of the boy king Tutanhhamun, an historical figure that has been the subject of many investigations, several movies, many works of both fiction and nonfiction, and a parody by comedian Steve Martin. His place in world history is well-established.

 

He was born around 1341 BC and ascended to the position of Egyptian pharaoh of the 18th dynasty in about 1333 BC at the ripe old age of nine. He held that position until his death a decade later. One of the mysteries surrounding King Tut is his parentage. His father might have been Amenhotep III or maybe Akhenaten or maybe someone else.  His mother is equally controversial with some believing that she was Queen Tiye and others that she was Queen Kiya. This controversy continues and we may never know the truth.

There is also a great deal of speculation about what caused his death at such an early age. Everything from accidents, to medical problems, to murder have been postulated. In the search for these answers his body has been x-rayed several times and a CT scan has been performed at least once.

 

One of the x-rays showed a dense calcification at the posterior base of the skull and many postulated that this could be from a traumatic hematoma. The problem is that calcification (the addition of calcium to a scar, more or less turning it to bone) takes many months if not years. This would mean that he would have had to survive quite some time after the injury if indeed a blow to the back of the head caused this calcified area. In view of that, it is unlikely that a blow to the head in this region is what caused his death. Yes, some subdural hematomas that follow blunt trauma to the head can initially be small and nonlethal for many months and then can expand and cause death. But this would require the presence of a very large hematoma or a large amount of bleeding into or around the brain and apparently none of this was found in any of the examinations of the young man’s body. I think a blow to the head is very unlikely to have caused his death.

When discovered, his left femur (thigh bone) was fractured. Though this is a serious injury and can indeed lead to death from bleeding or from later infection or even from blood clots that form in the leg, break loose, and travel to the lungs as pulmonary emboli, many believe that the fracture of the femur occurred during the embalming process and was not a pre-mortem event. Again, it is unlikely that this was the cause of his death.

Others have suggested that he was poisoned, drowned, strangled, or that some other method of murder was used. There is no evidence to support any of these theories but they are interesting.

As far as a natural event causing his death, this is entirely possible but again there is no way of knowing. He was a very unusual looking young man. He had very large front teeth with a massive overbite and an elongated head, both of which were characteristics of his ancestors. He also apparently had a cleft palette and some degree of scoliosis. All of these findings could point to some musculoskeletal or connective tissue disorder such as Marfan’s syndrome. Marfan’s is a connective tissue problem where there is weakness of certain tissues. The joints tend to be loose, the palette tends to be high and arched, the lenses of the eyes can be displaced leading to visual difficulty, and the aorta can be weak and expand into an aneurysm that can rupture and prove deadly. Could this have happened to the young King Tut? Since the CT scan showed no evidence of an aortic aneurysm this is very unlikely if not impossible.

And so the mystery remains.

The Death of King Tut

Tutankhamun-Cause of Death

Mummification is one of the three main ways a body will change after death. The most common is decay, or putrefaction. This is a process mediated by bacteria and these bacteria prefer warm and moist environments. Most of the bacteria that cause decay of a corpse come from within the body, specifically the G.I. tract.

Under certain circumstances a body may undergo adipocere formation. Here the body takes on a waxy and mannequin like appearance. This is caused by certain acids and alkalis in the environment reacting with the body fats in a process similar to soap making. Once this process is complete, the body will appear like a pale white or grayish waxy doll.

For a body to undergo mummification, moisture must leave the body fairly quickly and leave behind an environment that is not friendly to bacteria. This can happen with a body dumped in a hot dry desert or one that is left on the hillside at a very high elevation where the air tends to be more moisture-free are even in bodies that are dumped into cool dry basements or closed up in the building crawl spaces. The bottom line is that a dry environment is essential for mummification.

The Egyptians were masters of the mummification process and Egypt’s hot and dry climate made their job much easier. Mummification follows from their basic religious beliefs in an afterlife where the person would need his body on the other side. By mummifying the body, it is protected, hopefully for all time. Since we have found mummies that are thousands of years old and are still incredibly well preserved, they seem to have accomplished their goal. But how did they go about doing it?

The process really addressed three goals: removal of the internal organs, dehydration of the body, and preservation of the tissues. The removal of the internal organs was essential to prevent decay since corpse decay begins inside the body. The ancient Egyptians did not have the knowledge of exactly what the decay process was or that it was mediated by bacteria or that these bacteria needed warmth and water, but rather they made the empiric observation that the internal organs decayed readily and their removal would slow or halt this process. They tended to remove all of the intra-abdominal organs, and were quite elegant at removing the brain through the nose or through small holes drilled of the skull, but they almost invariably left the heart behind. The lungs would be taken, but not the heart, indicating that it held great importance to them. The removed organs would be preserved by wrapping them in oil or resin soaked lenin and placed in ornamental jars around the tomb. I imagine this was done so that when the individual awakened on the other side he could simply reinsert his organs and carry on.

The next issue was to dry out the body. This removal of moisture from the tissues prevented bacterial growth and decay. They used various salts and oils and other solutions to accomplish this. Things such as myrrh, salt, natron (a combination of various sodium-containing compounds), mineral spirits such as turpentine, and other dehydrating herbs were used. Linens, soaked in resins, cedar and other oils, and other chemicals, were stuffed into the body cavities. These helped dehydrate the body and likely had some antibacterial effects.

The bodies were typically wrapped in linen soaked with oils and resins and sometimes beeswax or plaster was placed over the outside to serve as a final protective coating.

I imagine each mummy maker at his favorite technique and chemicals.

Making an Ancient Egyptian Mummy

Mummification in Egypt: An Overview

 

 

Electronic Noses: Sniffing Out Corpses

When someone is reported missing and it is assumed that they’ve been murdered and dumped somewhere, it is critical for the police to locate the body, since this often gives them the critical clues that they need to determine who the killer was. There may be biological evidence associated with the body such as saliva or semen or blood or skin tissue under the victim’s fingernails. There might be hair or clothing fibers from the attacker. He might have left a fingerprint on the victim’s purse or belt or windbreaker or some other surface that would accept and hold prints.

Finding the body is critical.

The current Drew Peterson case comes to mind. The fact that his most recent wife disappeared and her body has yet to be found is greatly complicating the police investigation into her disappearance. And what about the other Peterson–Scott? Had the bodies of Laci and the unborn Conner not risen from the watery grave Scott gave them, he just might have gotten away with murder. Finding the bodies brought closure to the later Peterson case and hopefully will someday do the same for the former.

How are bodies located?

Let’s say that a young woman walks or jogs through a park or a wooded area on a regular basis and one day disappears while on one of these walks. The police would search that entire area, assuming that if the attack took place on that trail, the body would likely be left somewhere near that path.

First the police would spread out along the trail to see if the body was left nearby. If this was a murder of passion or of opportunity, the killer might not have a plan for body transport and disposal so he would want to get rid of the corpse as quickly as possible. That means he likely dumped or buried the corpse near where the attack took place. So, the best place to look would be near the trail—particularly on the downhill side. Dead bodies seem to weigh a lot more than the person did when they were alive (not true just seems that way) and carrying a dead body uphill is not easy. Downhill works much better.

Investigators would look for disturbances in the ground or interruptions in the normal vegetation that might reveal a recently dug grave. Freshly turned dirt, trenches, or elevations or depressions in the terrain might be helpful. Fresh graves tend to be elevated above the surrounding area, while older ones might be depressed. This is due to settling of the soil, decay of the body, and collapse of the skeleton. Interestingly, the depth of the depression is greater if the body is deeply buried. This is likely due to the larger amount of “turned” dirt, which is subject to a greater degree of settling and the increased weight of the dirt over the corpse, causing earlier and more complete skeletal collapse. This leads to a deeper depression in the soil.

If the corpse has been buried for a number of weeks or months, changes in the natural flora of the area might be seen. Decomposing bodies tend to make good fertilizer and often the flowers and shrubs that grow near the burial site will be fuller and more lush than those in surrounding areas. Often aerial reconnaissance from a plane or helicopter can uncover this. In addition, the plane could be equipped with infrared and other thermal devices that look for heat signals. Freshly turned dirt tends to lose heat more rapidly than does compacted soil so that thermal scanning might turn up a “cold spot.” On the other hand, an actively decomposing body tends to produce heat as one of the byproducts of decomposition and this might be visible on an infrared scanner as a “hot spot.” So any variation from the background level of heat found by thermal scanning should be investigated by searchers on the ground.

Other scanning devices are also used. Ground penetrating radar and side scanning sonar can often be used to locate bodies. In a fairly fresh grave, the soil is looser, less compacted. In addition, a decomposing body tends to add moisture to the soil. These types of scanners can often detect this loosened and/or more moist soil and thus locate the grave. Also, a simple metal detector might locate jewelry, belt buckles, cell phones, watches, or other metallic objects that the victim had on her at the time of burial.

A magnetometer is a device that looks at the magnetic properties of soil. In many areas, the soil contains small amounts of iron, which gives it a low level of magnetic reaction. Since the body itself has a lower magnetic reactivity than the soil, the magnetometer can sometimes detect this variation and help locate buried corpses.

Dogs play an important in corpse location.

Bloodhounds or other tracking dogs might be useful in that they can often track the victim from her home, along the trail, and then to the dump or burial site. Some bloodhounds have even tracked corpses that were transported short distances in automobiles.

Cadaver dogs might be brought in. These dogs are specially trained to sniff out the chemicals of decomposition. When a body decays it releases certain chemicals and these dogs are trained to locate them. They can find a body that is only a day or two old and in some cases ones that have been buried for 20 years. The reason is that the gaseous molecules that are produced during the decay process tend to hang around in the soil for a long time and are slowly released into the air. Though humans might not be able to detect the odor, a well-trained cadaver dog can.

But the days of these detective dogs just might be numbered.

More recently scientists have begun developing what is known as an Artificial Nose, Electronic Nose, or E-Nose. This is simply a device that detects the chemicals of decomposition as they are released into the air around a dump or burial site. It works on the same basis that a cadaver dog does. The released chemical molecules strike specialized receptors within the dog’s nose and if he is trained to recognize these chemicals he will alert his handler to that fact. The electronic nose has sensors that detect the same chemicals.

Many of these devices are simply small portable gas chromatographs, which can separate and identify many chemicals and in some cases determine the amounts of each. Newer studies are looking into using the new technology of microfluidics and LOCAD— Lab On A Chip. These are a spinoff of current research going on at NASA’s Marshall Space Flight Center in Alabama and other areas around the country.

Other uses of such an Electronic Nose would be to detect harmful environmental chemical contaminants, screen for bioterrorism toxins, and maybe even complement fingerprints and DNA as a method for identification. Sort of an Odor Print.