Prosopagnosia: I See You But Who Are You?

 

Heather Sellers doesn’t know who she is. I mean she knows, but she can’t recognize her own reflection in the mirror. Or the faces of others. She suffers from Prosopagnosia, or face blindness. It’s not as uncommon as you might think, but most often it is mild and only slightly aggravating.

Acquired prosopagnosia often results from head trauma, stroke, or developmental prosopagnosia (as Heather Sellers has) seems to genetically determined and begins at a young age, before the development of normal facial recognition abilities. How do these folks recognize family and friends? And themselves? Usually by some combination of voice, clothing, hair style, mannerisms, walking gate, body language, or some combination of these and other cues.

Here is an interesting video of someone who has this malady.

 

Fast Bullets and Broken Glass

Crime scene reconstruction is an art and a science. If investigators can determine what happened, to whom, when, where, and how, they are well down the road to solving the case. Ballistic trajectories are often part of this analysis.

 

What was a bullet’s direction of travel? Was the gun fired inside the house or outside? Better yet, what was the speed of the bullet? Directionality can refute or support suspect alibis and witness statements and bullet speed can narrow the type of weapon used when the bullet itself is not available.

It has been known for many years the glass fracture patterns can reveal directionality but now there seems to be a method for determining the projectile’s speed. Very cool technology.

 

 

From HOWDUNNIT: FORENSICS:

The lab might also be asked to determine how and why a glass object, such as window, fractured. The pattern of the breaks and cracks seen in a window give the examiner a clue as to the speed and direction of the impact; this helps him determine what object likely caused the break. Was the object moving at a low velocity, such as a rock or fi st, or at a higher rate, such as a bullet or explosive shrapnel?

Cracks in windows and other flat plates of glass tend to be radial and concentric.

Radial cracks spread outward from the point of impact in a spoke-like configuration. Concentric cracks are a series of progressively larger circles around the point of impact. Overall, the cracked window might look like a spider web.

Certain characteristics of a break allow the examiner to determine the direction from which the impact came. This can be critically important in crime scene reconstruction. Did the bullet penetrate the window from outside in, or was it fired from within the house? Did a perpetrator break the window and enter, or did someone within the house break the window in an attempt to stage the scene and make a domestic homicide look like a breaking-and-entering murder?

Stress-fracture lines known as conchoidal lines, which radiate away from the impact site (see Figure 15-3), can help make this determination. Viewed through the thickness of the glass, these lines tend to curve out and away from the point of impact. Looking more closely at these conchoidal fractures, smaller lines that radiate in a perpendicular direction from edges that face away from the impact site may be seen. These are called hackle marks.

Figure 15-3: Conchoidal fracture lines. Conchoidal fracture lines tend to curve out and away from the point of impact. Hackle marks also reveal the direction from which the force was applied.

 

If a projectile such as a bullet strikes a window and penetrates it, but does not completely shatter it, it may leave a hole with or without surrounding fracture lines. On the side of approach, the bullet creates a rather clean hole, while on the opposite side, a small cone-shaped plug of glass is forced out. Simple visual inspection of the impact site reveals the projectile’s direction of travel.

If multiple bullets or other projectiles fracture the glass, it is often possible to determine the order in which they struck. Typically, the radial fractures caused by the second object do not cross those of the first. That is, they end when they encounter glass that is already fractured (see Figure 15-4).

Figure 15-4: Intersecting fracture lines. Impact radial fracture lines end abruptly at those produced by a previous impact. In this case, fracture B followed fracture A.

 

These findings can be extremely important in corroborating or refuting suspect and witness statements and in reconstructing the events surrounding the crime. They can also be useful in assigning culpability.

Let’s say two gang members decide to do a drive-by shooting of a rival gang member while he is sitting in his car. The driver fires through the victim’s car window and begins to drive away. His accomplice then takes the gun and fires again. Both bullets pass through the window and strike the victim, one in the shoulder and the other in the head, killing him. Since both bullets came from the same gun and both men have gunshot residue on their hands (see Chapter Sixteen: Firearms Examination, “Gunshot Residues”), which of the shooters was the actual killer? Was it the first bullet (the driver) or the second (the passenger)? The dilemma is resolved when analysis of the fracture lines in the victim’s car window reveal that the second bullet was the killing shot.

 

 

Q and A: Can My ME Determine If a Child Died From Exposure As Opposed To Being Locked in a Heated Vehicle?

Q: In my story, a police officer is on the scene where the body of a 3 year old child was found among the rocks and weeds of a dried up riverbed in Southern California. It is early summer. Can the CSI techs or the ME determine if the child died from being locked up in a heated car rather than from exposure to the elements where the body was found?

Jack Dietz, Production Coordinator, Las Vegas, NV

A: The simple answer is that this is not very likely however there might be a way. Much depends on the condition of the body. If it is severely decayed or has become skeletal, the ME would have little to work with and there would be no way to determine exactly where the death occurred. In either case the death would be from that catchall term “exposure.” What that means is that the victim died from lack of water or food, with water of course being the most important. Exposure deaths are almost always due to severe dehydration.

However, if the child is found within a day or two of death, the body would be more or less intact and the ME might be able to estimate where the death had occurred, given the two choices you outlined. One difference would be insect activity. If the child died in the trunk as opposed to being exposed outdoors there would be less insect activity for the amount of time since death than would be expected from an exposed corpse. If the ME determined that the child had been dead for 2 or 3 days yet there was essentially no insect activity, it would mean that she had been in a protected environment, such as an enclosed car or car trunk, for those 2 or 3 days and only exposed for maybe a few hours. On the other hand, if he found insect activity that matched his estimate of the time since death, this would favor her being in an exposed environment for those 2 to 3 days. It’s not that flies can’t get into car trunks, it’s just that most trunks are so well sealed, fly access would be very limited, if at all.

On a similar note, predatory animals would not be able to attack the body while it was in the car but if exposed predator feeding on an exposed body is fairly common. Coyotes are everywhere. Predator activity would suggest a longer period of environmental exposure.

 

One circumstance that might be interesting for you would be if the child died in either the trunk or on the floorboard of the car. As she died from hyperthermia and dehydration, she would increasingly gasp for breath toward the end of her life and could inhale carpet fibers from the trunk lining or floor carpets. This would not happen if death occurred while exposed outside. This would of course require that the body be in fairly good condition. I think as long as you have the body found within a few days, the decay process would not have progressed far enough for the lungs to be destroyed and the medical examiner might see these fibers during his microscopic examination of lung tissue. Once he found these fibers, he would know that the victim had inhaled them and therefore was alive while in the car. So finding the fibers would at least allow the medical examiner to guess that she had been in the car near or shortly before her death.

 

Another interesting thing about this scenario is that the ME could then analyze these fibers physically, optically, and chemically and determine the manufacturer of the carpet and this in turn could lead to the car manufacturer and even the make and model year–or at least a narrow range of years since car manufacturers change their products quite frequently. This would greatly help your police officer develop suspects.

 

 

DNA in a NY Minute

 

Writers often send me questions about DNA, and most include something about the turn around time for DNA analysis. Ten years ago the answer was weeks, five years ago hours, and now it seems only minutes are required.

Engineers at the University of Washington and scientists at NanoFracture, a company in Bellevue, WA, have developed a DNA extractor that uses electrodes and not spinning centrifuges to perform the critical and time-consuming step of removing DNA from any body fluid. And it does so in only a couple of minutes. Then on to a sequencer and before you know it you have a DNA profile.

Though not commercially available yet, this technology exists and it will be interesting to see how it progresses. Of course, it’s fiction-ready right now.

 

ThrillerFest Schedule

Here is this year’s ThrillerFest Schedule. Looks like a fun week.

If you haven’t signed up yet, do.

http://www.thrillerfest.com

 

Stupid Criminals: Butt Dialing Murder

 

 

Scott Simon needs to control his cell phone. It simply won’t behave. I mean all he did was slip it in his pocket. That’s it. Well, and apparently discuss a premeditated murder in progress with his buddy. The problem? His phone did the old 911 butt dial thing. Oops.

 

 

 

Deadly Scotch?

Yesterday I posted about a nut job who apparently whipped up an OJ and Rubbing Alcohol cocktail and left it a Starbucks. Scary. But now it seems that TGI Fridays and other restaurants in New Jersey might have done the same thing with Scotch. Really? If this is true they are guilty of poisoning their Scotch drinking customers.

Some things make you scratch your head.

 

 

Deadly Screwdriver

Screwdrivers can be dangerous. Not only the ones used to tighten and remove screws, which can be lethal weapons, but the ones you get at your local bar. OJ and Vodka. Nice way to get hammered and up your vitamin C intake. Multitasking.

But Ramineh Behbehanian apparently has her own recipe. OJ and alcohol. Not vodka or even ethyl alcohol (ethanol–the kind you drink), but isopropyl alcohol (isopropanol–rubbing alcohol). It seems she whipped up a couple pf bottles of this concoction and placed them in the refrigerated section of her local Starbucks. Fortunately, someone observed her doing it and called the police.

Maybe this was simply a prank. Maybe she innocently thought isopropyl alcohol and ethyl alcohol were interchangeable. No harm, no foul. Maybe. Except she’s a pharmacist. She knows the difference.

So what is isopropyl alcohol and why is it dangerous?

From HOWDUNNIT: FORENSICS

Isopropanol

Isopropanol is also an intoxicant and a CNS depressant whose effects usually appear within ten to thirty minutes after ingestion, depending upon the amount consumed and whether food or other beverages are taken as well. Fifteen to 20 percent of ingested isopropanol is converted to acetone, which produces acidosis (excess acid in the body). This greatly complicates things. The victim appears drowsy and off balance, and possesses a staggering gait, slurred speech, and poor coordination. Nausea, vomiting (sometimes bloody), abdominal pain, sweating, stupor, coma, and death from respiratory depression may follow. Hemorrhage into the bronchial tubes (breathing tubes or airways) and chest cavity may occur.

Isopropanol also absorbs through the lungs and the skin. Not infrequently, infants experience isopropanol toxicity from alcohol-and-water sponge baths used to treat childhood fevers.

As they say: Don’t try this at home.

 

PTSD: Blame Your Hippocampus/Amygdala Complex

PTSD is an increasingly common psychiatric condition that has many origins and manifestations. As with most psychiatric conditions there has been a long of history of scientists searching for some physical explanation, or at least an underlying substrate for these conditions. Everything from schizophrenia to criminal behavior has been studied. PTSD is no different.

Now a new study from Duke University, published in the Archives of General Psychiatry last November, sheds new light on possible anatomical changes in those susceptible to developing PTSD. This alteration lies deep in the brain in the hippocampus/amygdala complex, which is part of the larger Limbic System, areas of the brain associated with emotions, stress responses, learning, memory, socialization, and many other things. The researchers studied 200 combat veterans and found that PTSD sufferers tended to have smaller amygdalar and hippocampal volumes as compared to “normal” subjects.

Does this mean we now have a test for determining who is vulnerable to developing PTSD? Not yet. But this study is a step in that direction.

My first Dub Walker thriller, STRESS FRACTURE, dealt with PTSD and its treatment.

 

 

Q and A: Can My ME Distinguish Death From Asphyxia From Death Due to Head Trauma?

Q: Here’s my book situation: A man puts a plastic bag over his head to kill himself. His wife wakes up next to him (after he nearly strangled her to death and she discovers he’s killed their son) and in her horror and rage cracks him over the head with a blunt object.

Here’s my question: Can the police/coroner/forensics determine which was the cause of death–suffocation or blunt force trauma? If so, what would the signs be pointing to asphyxiation?  Also, if it matters, this is set in 1969.

Judy Merrill Larsen, author of All the Numbers

http://www.judymerrilllarsen.com

A: If the victim died first from the asphyxia, the ME would have no problem since the blow to the head would cause no bruising or bleeding. At death the heart stops and blood flow ceases and a corpse will not bleed or bruise easily. So the ME would see a mark where the victim was struck but no bleeding or bruising and know that the blow was delivered post-mortem.

If he was still alive when struck, things become a little more difficult for the ME but he should still be able to tell. Bruising and bleeding at the site of the blunt trauma would show that the victim was alive when struck but if there is no significant brain injury found at autopsy he would know that the force of the blow did not cause death and the asphyxia must have. If there is a brain injury such as cerebral contusion (brain bruise) or bleeding into or around the brain, he might have difficulty determining the actual cause of death. Of course any evidence of blunt trauma would point to homicide and not suicide since someone using a plastic bag for suicide would not likely also strike themselves in the head.

But I see a bigger problem with your scenario. If she was unconscious from being strangled, she would wake up within 10 seconds to a minute or so after the pressure was released unless she had significant brain injury from lack of oxygen. If she were simply strangled into unconsciousness, which is due to blocking blood flow thru the carotid arteries to the brain and not blocking breathing, as soon as the pressure was released and blood flow reestablished, she would wake up very quickly. Much sooner than he could put a bag on his head and die from asphyxia. For her to be out that long would require some degree of brain injury and I don’t think that’s what you want. Of course, if he drugged her first and then strangled her to the point he thought she was dead, but she in fact wasn’t, then she would awaken when the drug effect wore off. Here he could be dead for hours before she awakened.