Murder and Mayhem (29 page)

(the speed the bullet is traveling), the thickness of the cranium (skull bone), the angle at which the bullet struck the skull, and a few other factors. A large, soft, low-speed, hollow-point bullet would be less likely to pass completely through the skull than would a small, high-velocity, Teflon-coated one.

Q2: If the bullet does exit the skull, would there be a way for the pathologist to determine what type of ammo was used?

A2: Unless the bullet was very severely damaged by the skull and the wall or whatever it embedded in, the ballistics people could probably tell the type of ammo and maybe find some rifling grooves for comparison if the weapon or other bullets from the same gun were found. On the other hand, the bullet could be so fractured, flattened, or distorted that little of use could be gleaned. If the bullet wasn't found, an experienced M.E. might be able to guess the caliber and type of ammunition used from the nature of the bullet track through the skull and brain, but a definitive answer would likely be impossible. Again, it is your choice as to whether the bullet is identifiable or not. Either is realistic.

Can Stored Blood Be Used to Stage a Death?

Q: If someone removed and stored his own blood and later used it to stage his death, would the coroner be able to tell that the blood wasn't fresh? The scene I have in mind is a car over a cliff and into the ocean. No body would be found, but the victim's blood would be on the glass and upholstery, leading the police to conclude the body must have washed out to sea. Would the blood need a preservative to keep it from clotting? Could it

also be frozen and thawed? Would the fact that the blood was stored or thawed show up in the forensic tests? Would the salt water interfere with DNA matching?

A: The victim could remove his own blood and either use an anticoagulant (any substance that prevents blood from clotting) such as EDTA or let it clot, then refrigerate or freeze it. In a typical crime scene such as in a room or an accident on dry land, the M.E. might be able to determine if the blood had clotted beforehand by looking at the microscopic organization of the clot. Its architecture may make him suspicious that the blood had clotted before it reached the scene. For example, a large clot of blood lying on the carpet with no corona of blood soaking the carpet around it may look as though it was simply dumped there rather than bled there, which of course would be the case.

He might also be able to determine if unclotted blood had been frozen. He would look for fracturing of red blood cells, which occurs during freezing. Also, since blood clots very quickly after it leaves the body, if the M.E. found a pool of blood that hadn't clotted, he would likely conclude that some form of anticoagulant was present and thus the scene had been staged. He would then test the blood for the presence of an anticoagulant.

If the blood was flash frozen and later thawed out and dumped at the scene, where it would then clot, the M.E. would probably not be able to determine if the blood had been frozen. The clotting process itself fragments and destroys most of the red blood cells (RBCs) so that any fragmentation of the RBCs would be assumed to have occurred due to the clotting.

The M.E. might not be able to make a clear determination in any case, however.

In the scenario you describe, the car would be in the water, and probably beneath it, and this fact would change the evidence dramatically. Most of the blood would wash away so that the M.E.

would be dealing with residual stains on the seats, doors, and possibly the glass. He wouldn't expect to find clots or pools of unclotted blood in this situation. A square of the upholstery would probably be cut out and used for analysis.

He would be able to perform a DNA match since the stain would provide all the DNA he needed. The salt water wouldn't change this result.

There are two things the M.E. might find amiss that could raise his level of suspicion. One would be the bloodstain pattern. If it looked staged rather than the expected pattern in such an accident, he might question the scene. Another red flag would be an elevation of the anticoagulant EDTA in the blood, but only if he tested for it. EDTA is sometimes sprayed on vegetables in the grocery store to prolong their freshness, so we all have a trace amount in our blood. That means it would be very difficult to state that any level found in the victim was elevated. There is no normal level for comparison. Still, an excessive concentration might give him pause and give you a nice thread to follow through your story.

Would Glycerol Used as a Blood Preservative Likely Be Found in Blood Used to Stage a Crime Scene?

Q: In my story someone tampers with a crime scene by planting blood evidence from a bag of blood preserved with glycerol and then frozen. My questions are these: Does the M.E. routinely check blood obtained at a crime scene for evidence of previous freezing? Would freezing hamper DNA typing? If the blood was thawed by an amateur rather than being properly handled, would the blood have a similar appearance to fresh blood and would the presence of glycerol still be detectable even if it was not specifically being sought?

If a test was made on the sample for illegal narcotics, would the presence of glycerol be detected?

A; Blood at a crime scene is usually collected with cotton swabs, which are stored in glass vials until testing. Though microscopic examination of a liquid sample of blood might yield evidence that the blood had been frozen (ice crystal fragmentation of the red blood cells), this is not routinely done and couldn't be done from the blood collected on a swab.

DNA testing doesn't rely on intact cells, so freezing and thawing, clotting, or drying of the blood would have no effect on DNA matching.

The thawed blood, if spread around the floor or on furniture or bedsheets, would look like blood from any other source. Of course, the absence of clotting might suggest that the blood had some type of anticoagulant such as EDTA or glycerol added. This depends on how quickly the crime scene is discovered. If found immediately, any pools of blood would develop clots fairly quickly (in a matter of minutes) rather than stay liquid. If found later, these pools of blood will have clotted and will have a jellylike consistency. If they didn't clot, the M.E. would suspect the presence of an anticoagulant. If it is found even later, after the blood has dried, the M.E.'s task of determining whether the blood had clotted before drying would be difficult if not impossible.

Glycerol is an organic alcohol that has many industrial uses. It is the basic ingredient of the gums and resins used in exterior house paint and other protective coatings. It is used as an emulsifier and stabilizer in ice cream, shortening, and baked goods. It is used in the production of nitroglycerin. And relevant to your question, it is used as a protective medium for the freezing of red blood cells (to prevent the ice crystal fragmentation of the cells), sperm cells, corneas, and other living tissues.

Of course, if the M.E. tested for glycerol, he would find it, but that isn't necessarily part of a routine drug screen. Different labs

have different protocols for what they test and what they don't. This means that if it fits your story to have the glycerol not found, or vice versa, it'll work.

How Soon Do Strangulation Bruises Appear?

Q: If a person tries to strangle another, how soon would visible marks occur on the neck? What would be their nature? Would the pressure indicate whether the person was right- or left-handed?

A: The marks are basically contusions or bruises, just like those acquired when you run into a door or table. The bruising appears in a very few minutes. The seepage of blood into the tissues from damaged capillary blood vessels causes the bluish discolorations. If a victim is strangled to death, the heart stops beating, and the blood in the vessels clots fairly quickly. Once the blood has clotted, bruising is no longer possible. In other words, strangling a dead person will not leave bruises.

The bruises appear from the blood that seeps out during the strangulation, before death. It happens almost immediately, though the surface discolorations we associate with contusions may take several minutes to appear.

The typical strangulation marks are the same bluish discolorations around the neck. These marks often are very distinctive and may outline the fingers or, if it is a ligature-type strangulation, even reveal the pattern of the rope, chain, or whatever was used.

The more pressure, the more bruising. A right-handed person tends to have a stronger right hand, and vice versa for a lefty, so the M.E. might be able to determine handedness of the killer from the bruises. At least he might be able to make an educated guess, which is what a great deal of forensics is about anyway.

When Does a Decomposing Body Begin to Smell?

Q: All things being equal, roughly how long would it take for an undiscovered dead body in a home begin to smell strongly enough to attract the attention of neighbors?

A: In general, twenty-four to forty-eight hours. That's when the body would start to get ripe, and things would get worse from there.

Decomposition of dead bodies is due to two different processes. Autolysis is the aseptic (without bacteria) breakdown of the body's cells and tissues. It is due to the action of the enzymes that normally exist within the cells—sort of a "self-digestion." These are chemical reactions, and they are accelerated by heat and slowed by cold.

The second is putrefaction, which is bacterially mediated. The bacteria that cause this process come both from the environment and from the normal bacteria that reside in the corpse's colon. These bacteria, like the above-mentioned intracellular enzymes, prefer a warm and cozy environment. So putrefaction is also accelerated by a higher ambient temperature and slowed in a colder environment.

In your situation the corpse would begin to smell in roughly twenty-four hours or less in a bedroom in New Orleans in August; a week or longer in an unheated apartment in Chicago in January. In a more temperate climate, a day or two should do it.

Do the M.E. and Police Use Vicks VapoRub to Mask the Odor of Decomposing Bodies?

Q: What is the substance that many coroners place on their upper lip when visiting a crime scene or performing an

autopsy (presumably to offset the smell)? Does it have special properties, and, if so, can other substances (such as Vicks VapoRub) be used when it isn't available?

A: Yes, Vicks VapoRub is often used. Also, a surgical mask sprinkled with a peppermint concentrate is used by surgeons who must debride (the removal of dead and/or infected tissues) malodorous wounds such as those infected with gas gangrene (Clostridia). Trust me, the smell of this is absolutely the worst thing you can encounter. It will literally knot your stomach and make your eyes water. The peppermint helps marginally. If the debridement is extensive and takes some time to accomplish, several surgeons may work in rotation so they can spell each other every twenty minutes or so because the odor of gas gangrene is that oppressive.

When the police or the crime scene technicians must work near a decomposing corpse, they often swipe a bit of VapoRub on their upper lip to mask the smell.

Fortunately, our olfactory nerve (the nerve that connects the odor-sensing cells in the nose to the brain) fatigues quickly. This means its ability to transmit smell signals to the brain weakens as exposure to the odor continues, and thus the intensity of the odor declines. Everyone has experienced this. After a very few minutes a noxious odor becomes more tolerable, and a faint odor fades and may disappear altogether. Even the wonderful aroma of warm apple pie is most intense when first detected.

Does a Cold Room Delay Detection of the Odor of Body Decomposition?

Q: My scenario is as follows: A mystery writer comes home from a luncheon, has a nap, writes until bedtime, goes to bed, gets up the next morning, and works until lunch-

time, when the police arrive at the door. They are looking for her husband (a cop), with whom she hasn't lived for seven months; he didn't show up for duty the night before. The officers discover him dead in the den. The door was closed, and the air-conditioning has been on. These are my questions: Would the smell of the decomposing body be prevalent in the house after twenty-four to thirty-six hours? Is it plausible that the writer wouldn't know that the corpse is in the closed-off room?

A: The short answer is yes.

Body decomposition begins immediately after death. Bacteria, both external and those that live within the intestine, go to work on the tissues, and under normal circumstances the smell of rotting flesh is apparent in twenty-four to forty-eight hours. This timeline depends on many things, particularly the ambient temperature. A warm environment quickens bacterial growth and thus the process of decomposition (like an incubator), while a colder one slows it (like a refrigerator).

If the room is warm, the odor of decomposition may appear in twenty-four hours or less; if cool, due to a low outside temperature or from air-conditioning, it may take three or four days or more. In this case your timing would work out. The AC would slow the process, and the closed door would help contain the odor.

How Long Does It Take for an Unburied Body to Skeletonize?

B: My question is about a character who is killed and left unburied in the elements during May in the mountains of the Northwest. The area has had an early spring, with warm days and cool nights. Along with the usual animal population there are bears and big cats.