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Monthly Archives: December 2010

Q and A: Can the ME Match Hair Samples Taken 10 Years Apart?

Q:    Will hair samples taken ten or more years ago (like from a haircut) match current samples taken from the subject? For instance, could a tech using a comparison microscope be able to tell if they came from the same individual or would time have altered the person’s hair too much to tell except through DNA testing? (The subject is male, if it makes a difference.) And would there still viable DNA from the old sample to
make a DNA comparison to the new sample?

TMS, Florida

A:    Hair matching depends upon the physical characteristics of the hair shaft. The shaft of the hair possesses three parts. The central core is called the medulla, the surrounding portion the cortex, and the thin outer coating the cuticle. It’s similar to the number 2 yellow pencil you used in school. The lead would be the medulla, the wood the cortex, and the yellow paint the cuticle. The examiner looks at each of these areas when he attempts to match two hairs.


These characteristics are mostly stable, but color can change with aging, as hair turns gray in some people. But the make-up of the medulla and the pattern of the cuticle are stable. In a young or middle-aged person, the hair would not change a great deal over 10 years. Of course, treatments and coloring agents can make the examiner’s job more difficult but he still should be able to make a match.
Hair is predominantly class evidence. The examiner can say that two hairs are consistent with having come form the same person, but that’s about as far as he can go. But there are circumstances where hair can supply DNA, which is highly individualizing


Hair production and growth occur when follicular cells die, loose their nuclei (and DNA), and are incorporated into the hair shaft. This means that the hair shaft is composed of cellular debris and possesses no nuclear DNA. The follicle (bulb) is composed of living cells, which do possess DNA. If the hair has follicular tissue attached this can serve as a source of DNA, which can be used for fingerprinting and matching.
But what if the hair has been cut, as in your scenario, or has fallen out and has no attached follicle? Often, mitochondrial DNA (mtDNA) can be extracted from the hair shaft. Since the hair is built from cellular remnants, and since the cell cytoplasm houses mtDNA, it is possible to obtain a usable sample of mtDNA from the shaft of the hair. Mitochondrial DNA is passed down the maternal line unchanged and can be used to identify the maternal ancestry of the person in question. Often this is enough to make a positive ID.
For example, if the mtDNA of a hair found at a crime scene matches that from hair taken from the suspect’s siblings or other maternal-line relative (mother, grandmother, etc.) it proves that the person shedding the hair at the scene shared a maternal linage with the suspect’s relatives. This means that either he was there or one of his relatives was. Since Granny didn’t likely commit the crime, he must have. This evidence is not as strong as a nuclear DNA match but it is very powerful.


In your scenario, if nuclear DNA can be obtained from the bulbs of the two hairs, then an absolute match can be made. If mtDNA is all that is available and if the mtDNA matches, the examiner can say that the two hairs were shed by individuals who shared the same maternal linage. Or, as in your case, the hairs came from the same person. If the mtDNA and the physical characteristics both matched, this would be powerful evidence that the hairs came from the same person. Not absolute, but strong.

 
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Posted by on December 23, 2010 in DNA, General Forensics, Q&A

 

Stupid Criminals: Pacemaker Tracks Down Embezzler

So you have this perfect scheme figured out. Snatch $10 million from your company and disappear. Change your name, settle in another state on the other side of the country, enjoy your ill gotten money, and no one will ever know. Sounds like a plan.

But what happens when your pacemaker tells on you?

It seems that Roger and Peggy Gamblin did just that. Two years ago. They apparently embezzled $10 million from their company Flagler Title Insurance and disappeared to Colorado. Unfortunately for Roger he had a pacemaker and ended up visiting the hospital because of some cardiac issue. He of course used his newly fabricated Colorado name. When the physician caring for him checked his pacemaker, he discovered that it was not registered to the gentleman who had checked into the hospital but rather to one Roger Gamblin. He reported this to authorities and the Gamblins were promptly arrested.

You see pacemakers and other body appliances, such as artificial hips and the like, have serial numbers etched into them. These numbers are easily traced to the manufacturer, the doctor who implanted the device, the hospital where it was done, and of course the name of the person who received it. Such serial numbers are often used to determine the identity of an unknown corpse. A body that is found with no identifying paperwork but which has a pacemaker, an artificial hip, or some other medical appliance, can then be identified through the serial number on these devices.

In Roger Gamblin’s defense, he was probably unaware that his pacemaker could be tracked in this way. But even if he did, what was he to do? Take it out himself? Not go to the hospital when he was having some cardiac problem? Likely he was either unaware or simply hoped it would slide through the system without being picked up. Fortunately he was identified.

Don’t you hate it when something you trust tells on you? I remember as a kid, around age 5, me and a buddy decided we would climb this whistle tower at a mill a block from where I grew up. The goal was to grab an egg from one of the many pigeon nests tucked into the nooks and crannies just beneath the top platform. At 5 proving your manhood is a big deal. The tower was maybe 50 feet high, and of course local lore said that if the horn/whistle sounded while you were on the tower, you would be electrocuted and die. Now that is a challenge. What kid wouldn’t do that? So off we went.

Unfortunately for us, my dog decided this was not a wise idea and immediately ran home to get my mother. He pulled a Lassie on me. He barked at the door until mom answered and then led her–you know, barking, running, turning around to see if she was following–to where we were. Near the top of the tower.

That was the only dog I ever owned. Traitor. Now I have cats. Cats can be trusted. Cats are very circumspect. Or is it that they don’t really care what you do as long as you use your thumbs to open cans for them? At least that’s how it works with The Bean.

The Bean

 

Q and A: Can Silver Be Used to Kill a Werewolf?

Q: My hero knows the villain, a werewolf, is extremely allergic to silver. He has to introduce a sufficient amount into the villain’s system to put him out of action permanently. He doesn’t have to die but no longer be a threat. A vegetative state would be okay.

They are at a party to raise money to rebuild a church. The villain is a member of the church council so will be greeting the guests. The hero and villain have never met before.

The hero cannot be a suspect in the villain’s poisoning so he can’t offer him any food or drink with silver in it. If he gave the villain a check with silver powder sprinkled on it would it be enough to bring on a reaction? How soon would the reaction occur and what would be the symptoms? The party’s host’s son is a doctor. What actions would he take to save the villain?

A: What a wild plot. If I remember correctly from my childhood visits to the Saturday morning “Creature Features” at the local theater, a werewolf can be killed with a silver bullet to the heart. But, silver powder would work too if the werewolf was allergic to it.

A severe allergy to virtually anything can kill the allergic person. From peanuts to penicillin and everything in between. And yes, sliver, too. Particularly in the world of werewolves and other fantasy situations. If the victim is severely allergic, skin contact of a metal such as silver might very well produce a sudden and deadly allergic reaction. This would be called an anaphylactic reaction or anaphylaxis.

Our immune system is critical to our survival. We are constantly bombarded by potential antigens all the time, usually in the form or bacteria and viruses. The body recognizes the antigen (virus, etc.) as foreign and builds antibodies that will recognize and attach to the virus. This reaction attracts white blood cells (WBCS), which release chemicals that kill or harm the virus, which is then consumed by the WBCs and destroyed. This process is essential for each of us to survive in our bacteria and virus-filled world.

So far, so good.

But, in allergic individuals, this reaction can be rapid and massive and can cause the release of large amounts of the chemicals from the WBCs. This is the reaction we call anaphylaxis. In excessive amounts these chemicals cause dilatation (opening up) of the blood vessels, which leads to a drop in blood pressure (BP) and shock. They cause the bronchial tubes (airways) to constrict (narrow), which leads to shortness of breath, wheezing, and cough. This is basically a severe asthmatic attack and prevents adequate air intake and the oxygen level in the blood drops rapidly. The chemicals also cause what is known as capillary leak, where the microscopic blood vessels in the tissues leak fluids into the tissues. This leads to swelling. In the skin this is manifested as hives and rashes. In the lungs it causes swelling of the airways, which along with the constriction of the airways, prevents air intake. In the tissues it causes swelling of the hands, face, eyes, and lips. The net result of an anaphylactic reaction is a dramatic fall in BP, severe wheezing, swelling and hives, shock (basically respiratory and cardiac failure), and death.

So, anaphylaxis is a rapid and profound reaction to some antigen. These antigens are typically foods, drugs, or insect venoms. Common foods are peanuts and shellfish, common drugs are penicillin and iodine, which is found in many radiographic dyes, and common insects are bees. There a myriad other foods, drugs, and bugs that can cause anaphylaxis in the allergic person. And in your scenario, silver would work.

Usually anaphylaxis onsets within minutes (10 to 20) after contact with the chemical, but sometimes, particularly with ingested foods, it may be delayed for hours—even up to 24 hours. In your scenario it would take from 10 to 30 or so minutes to begin and your werewolf would then develop all the above symptoms and signs. He would become very short of breath and develop hives and a rash. He might wheeze and gasp for breath. Finally he might clutch his chest and collapse into shock and die.

Untreated anaphylaxis leads to death in anywhere from a very few minutes to an hour or more, depending upon the severity of the reaction and the overall health of the victim. Treatment consists of blood pressure (BP) and respiratory support, while giving drugs that counter the allergic reaction. BP support may come from intravenous (IV) drips of drugs called vasopressors. The most common would be Dopamine, Dobutamine, epinephrine, and neosynephrine. Respiratory support may require the placement of an endotracheal (ET) tube and artificial ventilation. The victim would immediately be given epinephrine IV or subcutaneously (SubQ) and IV Benadryl and steroids. Common steroids would be Medrol, Solumedrol, and Decadron. These drugs work at different areas of the overall allergic reaction and reverse many of its consequences. The victim could survive these interventions. Or not. Your call. And if he survived he could easily suffer permanent brain damage and be in a vegetative state.

 
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Posted by on December 15, 2010 in Cool & Odd-Mostly Odd, Medical Issues, Q&A

 

Guest Blogger: 10 Most Incriminating Types of Evidence

Guest post from my friends at Criminal Justice Degrees Guide

Evidence is crucial for ruling out suspects, finding criminals and proving their guilt. Many criminals go to great lengths to cover up their crime and leave no feasible trace of evidence, but major advances in forensics and investigation practices have made it possible to dig up various types of evidence that are admissible in court and bring police closer to catching criminals. Here are the 10 most incriminating types of evidence:

1-Fingerprints: Fingerprints are the most incriminating types of evidence used in criminal cases because it’s one of the most reliable forms of identification. No two people have the same fingerprint, making it a truly fundamental tool for accurate identification of criminals. Only when fingerprints can’t be traced back to a person with a criminal history do they have less power in an investigation. However, if the suspects can be narrowed down, their fingerprints can be tested to see which one matches.


2-Blood: Blood is an incriminating type of evidence for various reasons. DNA can be extracted from blood to find a criminal and blood type can be analyzed to help rule out suspects. Blood splatters can also help investigators piece together crime scenes and it provides more evidence to test.

3-Hair: Hair is another useful type of evidence that can bring police closer to a criminal. A strand of hair collected from a crime scene can be submitted for DNA testing. Forensic scientists may have a better chance at testing the DNA if the hair follicle is still intact. In addition, the color of a hair strand can also be used to rule out suspects whose hair does not match the recovered hair sample.


4-Skin: Although difficult to see at a crime scene, skin can be analyzed and tested to find a criminal. Like hair, skin samples can help determine the skin color of the person involved in the crime and DNA can be extracted for a more accurate identification of criminals. Skin can also be a harbinger of other evidence at the scene, which brings police closer to finding the criminal and understanding the crime in greater detail.

5-Witness Testimony: Testimony from a witness who was at the scene of the crime is one of the most incriminating types of evidence. How incriminating the testimony is depends on the credibility of the witness, which is determined by the jury. It can be the deciding factor in a case.

6-Written Documents: One of the worst things you can do as a criminal if you want to evade the law is write things down. Some criminals write in dairies, journals, letters and even e-mails to chronicle their plan of action or confess their guilt. Suspects may be in correspondence with others who can present these documents to police, or investigators may find such documents when searching a suspect’s home.


7-Semen: Semen can be used in several ways to verify rape accusations, as well as extract DNA to identify the criminal. Semen can also be analyzed and tested to determine if there was more than one person involved in a sexual crime.

8-Shoe Prints: Shoe prints are extremely useful in police investigations and they can be a very incriminating type of evidence. Police can tell by a lot about a shoe print, such as the make, model and size of a shoe, as well as the gender and approximate height of the person. Shoe prints also indicate the activity of the wearer when the print was made and, if the impressions are visible, police may be able to trace the criminal’s moves and follow their prints to the next destination, such as a nearby home or woods.


9-Videotapes/Photographs: Videotapes and photographs are both compelling and incriminating types of evidence. Whether the videos or photos capture the crime taking place or the people present during or after the crime, it is valuable evidence that can be used to rule out suspects and find the criminal.

The VISAR System

10-Ballistics: Ballistics is the study of firearms and ammunition. This technical form of evidence includes shell casings, gun powder, bullets, gunshots and other firing characteristics of a weapon. Even the slightest remnants of a gunshot can be traced to a specific firearm, where it’s sold and its owner, if registered.

 

Bacteria and Time of Death: A New Forensic Tool?

One of the most important things the medical examiner must determine in a death investigation is the time of death. This alone can exonerate some suspects while pointing the finger at others. It can confirm alibis or explode them. It can verify witness statements or reveal them to be false or mistaken. In any murder investigation the time of death becomes a focal point.

Unfortunately there are few, if any, reliable methods for estimating the time of death. Body temperature, rigor mortis, and lividity are simply too inaccurate and fraught with too many variables to lock down the time except in the broadest of ranges.

Perhaps stomach contents are somewhat more reliable but even they can be erroneous. In general the stomach empties 2 to 3 hours after a meal. This means that if a victim was known to have eaten a certain substance at a certain time and that substance is found undigested in the victim’s stomach, the medical examiner can conclude that the death must’ve occurred in less than three hours after the meal. Sounds simple. But even this is unreliable since various food materials digest at different rates and the rate of digestion varies from person to person. The consumption of alcohol or other drugs along with the meal can significantly delay this digestive process.

As you can see, this and the other methods for determining time of death present a problem.

Additionally, if a corpse is buried or tossed into a body of water each of these variables changes. The drop in body temperature, the onset of rigor, the pattern and onset of lividity, and the onset and rapidity of decay can be greatly altered by these environments, making the determination of the time of death even more difficult.

 

 

A new study that will soon be published in the journal Forensic Science International presents research done by forensic biologist Gemma Dickson and colleagues at the University of Otago in Dunedin, New Zealand. They studied what would happen to a body in a submerged environment, where the normal insect activity seen with corpses discarded on land, would not be in play. They used adult pig heads in the study and periodically sampled the bacteria that populated the skin. They found that the bacteria that colonized the tissues changed through the various stages of decomposition and that these changes just might be useful in determining a more accurate time of death. Much more research must be done to determine if this is indeed a useful and accurate tool but it is intriguing.

 
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Posted by on December 9, 2010 in Time of Death

 

Q and A: What Common Substance Could My Amateur Sleuth Use to Determine If a Stain is Blood?

Q: In my next mystery an amateur sleuth finds a stain on a wood floor under a rug. Is there a common substance she could use to determine if it were blood?

SCurran, Monroe, WI

A: There are a couple of easily obtainable chemicals that could be used for this. The first is phenolphthalein which was one of the first chemicals used to test for the presence of blood. It is readily available in most pharmacies and can be ordered online. There is a link below so you can see a company that sells the stuff and what it looks like.

 

Another thing that is purchased in any pharmacy are urine testing strips. These test for many chemicals but one of the things they test for the blood. There are several absorbent squares on the test strip one of which is a test for blood. Simply moistened the strip or moistened the staying and press the strip against the reaction will occur very quickly and this is a sensitive test for even small amounts of blood. Definitive testing to determine if it is indeed blood or if it is human blood or love a more sophisticated but these two testing methods are highly sensitive for even very small amounts of blood.

 
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Posted by on December 5, 2010 in Blood Analysis

 
 
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