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Monthly Archives: April 2011

Los Angeles Times Festival of Books this weekend

This weekend the Los Angeles Times Festival of Books will be held on the USC campus. I’ll be doing a pair of signings on Sunday, May 1st. Drop by and say hello.

This year is the 20th Anniversary of the FOR DUMMIES brand and as part of the celebration I’ll be signing FORENSICS FOR DUMMIES at the Wiley Booth (#745) at 2 p.m.

Then at 3 p.m. I’ll be signing STRESS FRACTURE and my other books at The Mystery Ink Booth (#370).

I hope to see many of you there.

 

Stupid Criminals: Tattoo You

We’ve all heard of cases where a suspect or a corpse was identified by his distinctive tattoo. And other criminals have been done in by maps and “To Do” lists recovered by the police. You know, the dude had a hand-drawn map to the victim’s home, maybe even a sketch of the interior, and a list that reminded him of everything he had to do to do the deed. Things like: gloves, mask, duct tape, gun, and, oh yeah, top off the gas tank in case a chase ensues.

One Anthony Garcia can top all of that. He supposedly belongs to the Rivera-13 gang in Pico Rivera, CA. He allegedly shot and killed 23-year-old John Juarez in a liquor store 4 years ago. He got away with it. Almost.

LA County Sheriff’s Department homicide investigator Kevin Lloyd was flipping through a collect of gang member tattoos when he stumbled on Garcia’s image. Imagine his shock when he saw that Garcia had a detailed tattoo of the crime scene splashed across his chest under the banner “Rivera Kills.”

It’ll be interesting to see how they use this is court but one thing I know for sure—if you put this in a book, no one would believe it.

 

Question and Answer: Is It Possible For My Character to Commit a Murder by Causing a Transfusion Reaction?

Q: In my story, an elderly and seriously ill man is murdered by a nurse who switches the blood he is to receive, causing a reaction, which kills him. How does this reaction occur and what symptoms would the victim have?

A: Transfusion reactions come in many varieties. They may be as mild as a rash or perhaps chills and fevers or may be so severe as to cause death. First let’s look at why these reactions occur.

The red blood cells (RBCs) are the carriers of Oxygen (O2) from the lungs to the tissues and of Carbon Dioxide (CO2) from the tissues to the lungs. This is accomplished by using the hemoglobin inside the RBCs. The RBCs also have Antigens on their surface. It is these antigens that cause the problem.

These antigens are designated either A or B. From these our blood typing system (ABO System) has been derived. Type A blood has only A antigens, Type B only B antigens, Type AB both, and Type O neither.

Simple so far. But, the serum of the blood (the liquid part) also carries antibodies. It is the reaction of these antibodies with the antigens of the transfused blood that causes problems.

Type A serum (that is the serum of people with Type A blood) has Anti-B antibodies. Type B has Anti-A antibodies. Type AB has neither. Type O has both Anti-A and Anti-B antibodies.

TYPE            Antigens on RBCs            Antibodies in Serum
A                             A                                       Anti-B
B                             B                                       Anti-A
AB                        AB                                      None
O                       Neither                           Anti-A and Anti-B

Reactions occur when blood with the right Antigen is given to a person with its corresponding antibody. For example, if a Type A person (who has Anti-B antibodies in the serum) receives Type B blood (which has the B antigen on its RBCs) or Type AB blood (which has both A and B antigens) an adverse reaction will occur because the Anti-B antibodies in the recipients serum will react with the B antigens on the transfused RBCs. This is a transfusion reaction. The result is agglutination, or “clumping,” of the blood cells and the release of several harmful chemicals, which cause the symptoms and signs of this basically “allergic” reaction.

It gets more complicated than this because there are a multitude of other antigen-antibody problems with blood matching. Antigens like the well-known Rh Factor, which is either Positive or Negative, and many others, mostly named after the physicians that discovered them. Your “blood type” is typically expressed only in terms of the ABO and Rh systems. For example, a person who is A-Positive has Type A blood and the Rh Factor Antigen is present, while a person who is O-Negative had Type O blood and the Rh Factor is absent.

Because of the multitude of potentially problematic antigens, prior to transfusion blood is “Typed and Cross Matched.” This is done to test the donor’s blood directly against the recipient’s blood for any antigens and antibodies that might cause the blood to be “incompatible” and thus, lead to reactions. In very emergent situations such as gun shots, stabbings, or automobile accidents where the victim is bleeding to death and there isn’t time to do a complete Cross Match, “type specific” blood is given. A person’s blood type can be determined in a few minutes but cross matching may take hours. In these cases, a Type A person receives Type A blood and everyone hopes for the best.

Another option in these situations is to give “Universal Donor” blood. This is Type O Negative. Since Type O RBCs have no surface antigens they are the least likely to cause a reaction regardless of the recipient’s blood type. Reactions can still occur due to other antigens but in an emergent situation, as I said above, you give the best blood type available and hope for the best.

In your story, I would suggest that you have your victim be Type A and have the nurse switch the blood for Type B. This could definitely cause a reaction. The patient would develop fever, chills, and a diffuse, irregular red rash over his entire body. This could begin within minutes or might be delayed for a few hours. He might develop a full blown anaphylactic allergic reaction, which would be the above symptoms plus, shortness of breath, low blood pressure, and severe shock with pallor, cold and clammy skin, and a bluish tinge to his lips and fingers and toes. Since this represents the severest form of allergic reaction, it would develop fairly quickly and could lead to cardiac arrest and death. If the victim survived all this, it is possible that his kidneys would be severely and irreparably damaged, even requiring dialysis.

Note: This is a very complex topic. If you want to know more, start HERE.

 
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Posted by on April 19, 2011 in Uncategorized

 

Joint Fluid and the Time of Death

One of the most important things that the medical examiner must determine in any death investigation is the time of death. This can spotlight or exonerate a suspect and support or refute a witness statement. An alibi can be upheld or shattered.

But it’s not that easy. The medical examiner uses things such as body temperature, degree of rigor mortis, lividity, stomach contents, degree of decomposition, insect activity, and a few other parameters to make a best guess as to time of death. Another determination that often proves helpful is the potassium level within the vitreous humor, the liquid inside the eyeball. The potassium level tends to increase in a linear fashion and at a known rate after death and this can help the medical examiner with his estimation.

Now it seems that assessing the level of potassium in the victim’s synovial fluid might be just as accurate. Synovial fluid is the liquid that lubricates our joints. This could prove useful in cases where the victim has been decapitated or the head is so damaged that the eyes have been destroyed.

 
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Posted by on April 14, 2011 in General Forensics, Time of Death

 

Question and Answer: Will Electroshock Therapy Help My Depressed Character?

Q: I need to know about shock therapy for depression. One of my characters is severely depressed and has tried all the medications. Is shock therapy still done? How is it done? Does it work? What are the complications?

A: Electroconvulsive Therapy (ECT) was and remains a very controversial topic. The truth is that it helps some people and others it doesn’t or might even harm. Unfortunately, that’s true of so much of medicine.

Major clinical depression is a common and significant medical problem. It robs the sufferer of all that is good about life. They are sad, lonely, see no future, enjoy no one’s company, avoid social activities, cry, and often fail to care for themselves. In its severest form, their clothes are dirty, they don’t bath, they eat poorly if at all, and as a result their health declines due to this personal neglect. The mortality rate in severe depression approaches 15 percent, mostly due to suicide.

ECT was discovered in the 1930’s. Over the years, many methods have been used to invoke the convulsions necessary for this type of treatment. Initially drugs were used, then insulin, which drops the blood sugar to such low levels that a seizure occurs. Finally, electric shock delivered to the brain was employed.

The mechanism of its action and benefit is poorly understood. It seems as though the chaotic electrical activity that rages through the brain during a generalized seizure somehow alters the “mood center” of the brain. No one knows for sure, only that the results can be dramatic.

In the early years, ECT was done without anesthesia so that when the seizures occurred the recipients would sometimes severely bite their tongues, vomit and aspirate, or even break bones in their extremities from the violent nature of the provoked convulsions. Pleasant.

In 1975, the movie One Flew Over the Cuckoo’s Nest hit the screen and painted a negative picture of ECT. Here it was used as a punitive device as opposed to a therapeutic endeavor. Currently, it is making a come back, because in many cases it works. Some studies report response rates of 80 to 90 percent as a front-line therapy and in those who have failed medical therapy, as in your character, it is effective in 50 to 60 percent of cases. Other experts refute this data. As with any therapy, relapses after ECT can occur.

I witnessed a couple of these during medical school. Not pleasant but in both cases it seemed to help. At least acutely. How it worked out long-term for these folks I don’t know.

The procedure is much less barbaric than it once was. The patient is placed on a stretcher, an IV is started, cardiac monitoring electrodes are placed on the chest, and the ECT electrode patches are applied to each side of the head. Either an Ambu bag with face mask is placed over the mouth and nose or an endotracheal tube is introduced into the trachea (wind pipe) in order to ventilate the patient during the procedure and until the anesthetic and muscular paralytic agents wear off. The patient is then given a short acting general anesthetic and a muscle relaxant, which prevent the outward manifestations of the seizure and thus prevent the tongue biting and bone breaking of the past. Short acting anesthetic agents used in this circumstance might include: Diprivan (propofol) 25 to 50 milligrams (mgs) given IV and repeated as necessary; or Versed (midazolam HCL) 2 to 5 mgs given IV and repeated as necessary. Both are fairly short acting so that their effects are seen immediately and wear off quickly. Muscle paralytics used might include: Norcuron (vecuronium bromide) 0.10 mgs per kilogram (1 Kg = 2.2 pounds) given IV; or Pavulon (pancuronium bromide) 1 to 4 mgs given IV. Each of these take effect immediately, their dosing can be repeated as necessary, and wear off over 20 to 30 minutes.

 


The physician performing the ECT pays close attention to the patient’s heart rhythm and airway, to prevent complications from aspiration or cardiac arrhythmias. The electrical current is applied to the brain and the seizure activity is induced, but since the patient is anesthetized and paralyzed, no tonic-clonic jerking, which happens in generalized seizures, occurs.

For severe depression, the treatments are given three times a week for six to twelve treatments or until the desired response occurs. Long term side effects appear to be minimal if any. Short term, there may be a dulling of cognitive function for a few days or weeks. Also, there may be amnesia, which can be retrograde (events that occurred prior to the ECT) or anterograde (events that occur in the period just after the ECT). In either case, these tend to resolve over a few days or weeks.

Besides this treatment being effective, it does not have the long term problems and side effects of the various psychotropic drugs used in the treatment of depression. Each of these medications has significant side effects and interactions with other medications and certain foods.

 
 

Guest Blogger: DNA Fingerprinting and Wildlife Forensics

This is a cross post from my friend Dr. GV Rao’s Blog. Interesting information on the use of DNA in wildlife management in India.

DNA Fingerprinting and Wildlife Forensics

An important goal of the conservation management programs in Wildlife of the critically endangered species is the determination of parentage and levels of genetic diversity within the remaining population. Such determination is possible, with high rate of success, is by use of DNA based methods. Every living life form on earth contains the most basic building blocks of life – the Deoxyribonucleic Acid or DNA, which provides them their biological identity either as an individual, a species or a population as well as their geographical origin and evolutionary history. Using the understanding of DNA science, coupled with the presence of efficient molecular techniques to examine information in DNA markers (segments of DNA in the genome of organisms that reveal variations), biological information can be tapped, revealing otherwise unreachable information at all levels of life. Furthermore, with the support of specific statistical tools and bioinformatics to analyse DNA data, inferences about the biology of organisms can be done, thus providing essential details for evolutionary, population and conservation biology.

Wildlife forensics is a relatively new method for law enforcement around the world and has not yet caught up the attention of Indian wildlife experts. It uses the same principles as human forensics, with a few modifications. The difference is that wildlife forensics needs to be able to identify and distinguish between a variety of species, whereas human forensics is concerned with just one species – Homo sapiens. The advent and application DNA fingerprinting (in the mid 1980’s) has been essential for both wildlife and human forensics.

The aim of wildlife forensics is to provide information for the conclusive identification of the animal carcass, for conviction of offenders, and hopefully deter these acts. It is also active in various molecular genetic research aiding wildlife management and conservation.

DNA fingerprinting allows for the identification of an individual or species. DNA sample sizes may be too small, so DNA amplification techniques may be applied. This involves the amplification of the small amount of DNA wherein in a short period of time the amount of DNA is greatly amplified. DNA fingerprinting allows the questioned wildlife sample can be confirmed with a match to the standard sample maintained in the laboratory.

DNA fingerprinting is useful in Wildlife management in several ways including;

* individual identification for matching tissue samples from an illegal kill site to samples associated with suspect.

* species identification of unknown tissue samples involved in illegal commercialization and poaching

* includes identification of mixed game products – packed meats

* sex identification to enforce the violations of the wildlife acts

* parentage analysis for captive breeding programs

* applying a non-invasive DNA sexing method (through the use of feathers) on birds. For the success of breeding efforts {as birds of both sexes do not show any distinct differences in their external morphology (sexual dimorphism) at their juvenile stage as well as at their adult stage}.

The law requires that guilt of an accused under Wildlife protection acts be established beyond a reasonable doubt. To do this, the prosecution needs either eyewitness testimony or physical evidence. The Wildlife laboratories can provide this physical evidence and serious violations of wildlife laws can be investigated and prosecuted. The U.S. has a national lab, and Canada has various labs across the country and India has none except for a research lab – LaCones at Hyderabad. One of the longest running ones is The Wildlife Forensics DNA Laboratory at Trent University in Ontario, Canada. It was the first lab to produce DNA evidence to be accepted into a North American court involving a wildlife violation. In India the most important case to have caught the attention of Wildlife experts was the Salman Khan Black Buck case wherein I had conclusively proved that the carcass exhumed after postmortem was indeed a black buck and not a deer as some assumed it to be. Now the US handles over 50 cases a year, providing convictions with fines, whereas in India it is a dismal 2 cases per year with cases still being under trial.

There is a need to conduct more molecular genetics research for wildlife management and conservation. The question many of you may ask is what is the use of Genetic Consequences? Or what connection does wildlife forensics have with conservation and genetics? Well at the out set it gives you direction in possible increase in population size with a decrease in animals hunted, increase population size, decrease possibility of inbreeding, increase heterozygosity and in turn, increase fitness. Current research on the population structure of a highly endangered local freshwater crocodile (Tomistoma schlegelii) using DNA based methods to infer bio-geographical distribution of the species range within Malaysia and South East Asia is yielding important results.

A Forensic wildlife laboratory will also receive analysis costs from other organizations and research grants. It then provides information that can aid in the prosecution of an offender, who then pays a fine to the government. Further, in the future, similar techniques that are used in the human genome project could be transferred to wildlife forensics, and automation will be the key. Studies of populations using past genetic information and comparing it to present and future genetic information with the assistance of DNA databases could provide knowledge any genetic impact of wildlife forensics. It is important to note that other aspects could also affect the outcome, and these need to be taken into consideration when drawing inferences. Therefore the need of the hour is that all the Officers of the Indian Forest Service and Conservators of Forests should unite to demand for Forensic Wildlife Laboratories to meet the requirement for better Wildlife conservation.

Dr. GV Rao

Visit Dr. Rao’s Blog

 
1 Comment

Posted by on April 6, 2011 in DNA, Guest Blogger

 

DNA and Hair Color

DNA is one of the most important criminal investigative tools ever discovered. It identifies an individual with virtually 100% certainty. If someone leaves blood, semen, saliva, or some other bodily fluid at a crime scene and if it is found good condition, DNA extracted from the sample can accurately tie that person to the scene. Doesn’t mean he’s guilty just that he left DNA there. Something he’ll need to explain.

But what if there is no suspect? What if the person who left the sample is completely unknown as often happens, particularly with serial predators. These “stranger murders” are often the most difficult ones to solve because there is no apparent “connection” between the murderer and the victim.

This means that any descriptive evidence that can be obtained regarding potential suspects is of paramount importance. If someone witnessed a particular person running in the distance or a particular type of car cruising the neighborhood or a particular type of clothing is left behind, then these can be added to the offender profile and help narrow the search. This is one of the important elements of the Violent Criminal Apprehension Program (VICAP). Through this program violent crimes committed by unknown perpetrators are uploaded into databases. If multiple crimes perpetrated in various parts of the country have similar characteristics then the linkage of these crimes can often build a more firm description of any possible perpetrators.

For example, what if a murder in Florida had certain characteristics (method of murder, weapon used, method of body disposal, etc.) and similar characteristics were found in a murder in New Jersey? What if in Florida someone had seen the perpetrator from a distance and judged him to be a tall thin male while in New Jersey someone saw a black van leaving the scene? If these two crimes were never linked then police in both areas would not know that they were looking for a tall thin male who drove a black van. And so on. The more evidence that can be accumulated regarding serial crimes the better a description of possible perpetrators can be constructed.

Now it seems that hair color can be obtained from DNA. So a perpetrator who leaves behind a drop of blood might also leave behind evidence of his hair color. It seems that red hair and black hair can be determined with an accuracy of approximately 90% while brown and blond hair can be determined approximately 80% of the time. This is critical information in formulating a profile of the killer.

Of course if the killer has changed is or her hair color, this evidence could prove misleading.

 

 
5 Comments

Posted by on April 3, 2011 in DNA, High Tech Forensics

 
 
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