So most of you know that in addition to writing novels I also continue to conduct research in the forensic science. Some of it is probably quite boring but I thought you might find my latest paper interesting. We wanted to see how long after deposition we could detect blood on concrete. Concrete has spread across our world at an exponential rate and to no one’s surprise, CSIs must search it frequently for evidence. Blood is generally considered to be fragile and may “disappear” from sight after a few days. We’d like to get called to a crime scene immediately but that doesn’t always happen. A previous study had found bloodstains outside on a concrete wall about two months after deposition but we thought it may be possible to detect it much later.
We also wanted to test the effects on a completely exposed surface (to the elements) with the possibility of some foot traffic. I suspect that we could detect even older blood in a garage, warehouse, or basement floor. We decided to use the blood reagent Luminol because of its sensitivity to blood (1:1,000,000). Luminol is a chemiluminescent reagent that has a long history of use in forensic investigations. Here is a link to the paper if you want to read it (or need to fall asleep!).
As crime novelists I thought it might give you some ideas for a realistic scene. The technique could be used in any scene where blood may have been deposited. Some examples for your novel could include traffic accidents, drive-by shootings, or any other type of violent crime. DNA analysis would not be possible but your detective or CSI might be able to verify a statement from a witness, co-conspirator, or even a psychic! While our study used an “X” type pattern it is plausible that one may uncover footwear or tire impressions or other bloodstain patterns (like drag marks). It may be a great way to keep your reader engaged in the scene as they “discover” the evidence alongside your characters.
I have been a bit AWOL lately. Every now and then I need a vacation and this last one turned out to be quite a little adventure. So today I thought it would be interesting to talk about the next generation of crime scene mapping. When I first started crime scene work we used metal tape measures and did our crime scene sketching on large pads of paper. While paper isn’t obsolete, the next generation of crime scene mapping offers many advantages. Tape measures are a pain in the butt. They bend, they come loose, and sooner or later you drag one through a pool of blood (yuck!).
Over the years CSIs have been utilizing various laser based measurement devices. They vary from small hand held range finders (great for inside measurements) to Total stations (like the ones you see surveyors using). Near the top of that list is the automated laser based scanner. These types of units gained international exposure during the reconstruction of the car accident claiming the life of Princess Diana. These units are not in common use yet due to the cost (some in excess of $100,000.00) but more and more agencies are beginning to use them.
The above video demonstrates one such unit from Leica instruments. I’ve used a number of Leica products and found them to be top notch. The scanner is about the size of a small trash can and mounted atop a surveyors tripod. Once activated the unit will bombard the crime scene area (up to a distance of nearly 1000 feet) with millions of laser pulses which bounce off various surfaces and return to the unit. It will scan a full 360 degrees and 270 degrees above and below the unit. Basically everywhere except the unit location. A typical room can be scanned in a few minutes. CSIs can also link the unit with GPS which is really handy in outdoor crime scenes (especially ones in remote locations). The units can even operate in complete darkness.
Those millions of points create an exact three dimensional map of the scene that can be represented in a rotational diagram. It even records color. Utilizing the scanner software this virtual map allows CSIs to determine distances between any objects in the scene. No more missed measurements and the accuracy is phenomenal. The CSI can also zoom and pan around the image to view evidence from different perspectives. As you can see in the video, certain points can be hyper-linked to crime scene photographs or even text reports. This is a powerful tool for the reconstructionist and can be useful for prosecutors as well.
This is cutting edge stuff and you may want to consider using this technology in your next novel. Remember, this unit will record everything visible to the laser so it may even “find” a piece of evidence missed by your detective. Maybe your scene was mapped at night (dumped body or car accident) and a crucial piece of evidence wasn’t seen by the on scene responders. Then your protagonist can go back and find the crucial clue. Use your imagination and have fun with it!
Today I’ve been invited to share a post at Writing With the Top Down BLOG on this method of determining the three dimensional area of origin in bloodstain pattern analysis. I’d love it if you could stop by and take a look.
I love introducing you to cutting edge technologies that may turn your reader’s heads and make them turn the page. Forensics has never been a stagnant science. Dozens of researchers are pushing envelopes and making the imaginable come to fruition. One such device is the M-Vac. This recent addition to the CSI tool kit may revolutionize how we search for evidence and recover DNA that was previously unrecoverable. Vacuums are nothing new to the collection of trace evidence. I need to write a post on the history of the trace evidence vacuum which was introduced at early as the 1930′s. The M-Vac is the next generation trace evidence vacuum designed specifically for DNA collection.
Forensic scientists have made great progress in the collection, analysis, and turn around time of DNA testing in the last decade. The M-Vac uses a wet-vacuum method to release stubborn cells from evidence like clothing, textured pistol grips, and other surfaces where the samples may be hard to get at with swabs. It uses a DNA-free buffer solution that is applied and then recovered in one step through the application wand. The solution carrying the DNA samples is then deposited in a sterile collection bottle that can be tested for DNA profiles. The wand allows the CSIs to cover large areas and get into nooks and crannies that prove too difficult for swabs. Validation studies have indicated that the M-Vac collects 39 times more DNA than swabbing!
I’ve included a short video below that demonstrates some collection methods. One sampling procedure that wasn’t covered was the autopsy. I’m not sure what possible roadblocks may exist (if any) but it seems to me that this sampling method may prove very valuable in sampling certain areas of the victim’s body. Imagine sampling the neck in a strangulation case, genitals or breasts in a sexual assault, the wrists or ankles in a body dump where the victim was dragged, or even the victim’s hair. You may also get results from the outsole of a shoe used in a stomping or the hood of a vehicle in a hit and run. As the video indicates, this tech may open up new leads in cold cases as well. The possibilities are pretty endless it seems.
If your next novel deals with DNA evidence you might consider using a device like this. I suspect there are a number of CSIs and detectives who may be unaware of this technology. Imagine their surprise at reading about it in your novel.
I’ve written before about the role of the forensic entomologist in death investigations. These professionals can provide critical information regarding the time since colonization and postmortem processes. One aspect of their analysis that is being utilized for frequently is the use of insects (like maggots) to screen for the presence of drugs or toxins (like Malathion). Before I get into the process, let’s discuss why this type of testing might be undertaken. Obviously, the presence of illicit drugs like cocaine, heroine, MDMA, or amphetamines, may provide critical information about a possible cause of death, criminal activity, and victimology. In the same light, the presence of prescription drugs may also shed light on the victim and their physical or mental health. Likewise, the absence of certain drugs may also reveal important clues surrounding the victim’s state of health. Did they need the medication to maintain a certain quality of life or health status?
Why not just review their medical records? First, the victim may not have a complete documented medical history. Some people gain access to prescription drugs through illegal or unethical means. Family members (even spouses or parents) may be unaware of certain health conditions. Additionally, the victim may not be identified at the crime scene. Insects like maggots can removes significant biomass during the decomposition process and some victim’s don’t have any identification on them. We may be able to extract DNA but that will be of little help if their profile is not on file. We may be able to construct certain features or details about their lives based on their physical possessions (clothing size, piercings, tattoos, etc.) but the presence of certain drugs or toxins may provide that extra clue that helps to narrow down missing person profiles.
The concept of using insects for drug screening is pretty straight forward. While the victim’s tissues and fluids (blood, urine) degrade through decomposition; the larvae do not. In effect, they act as mini-reservoirs. Eventually they will undergo some kind of metamorphosis but if they are found on a body they can be tested. As adults they tend to eliminate the toxins rather quickly but even trace amounts of some drugs have been found in recently emerged adult flies. Some research has even detected drugs in beetle frass (excrement) and fly puparia years after death. Testing is begun by crushing or grinding the insect samples in something like a mortar and pestle. There are a number of different tests that can then be performed including Gas Chromatography / Mass Spectrometry (GC/MS), Fourier Transform Infrared Spectroscopy (FTIR), and radioimmunoassay (RIA). In many ways the testing sample is treated like any other biological tissue. The effects of various drugs and toxins on the rate of biological development (of the larvae) is not fully known. These types of exams primarily screen for the presence or absence of drugs and toxins. The effects of such substances on insect biology is another matter the entomologist must consider when estimating the postmortem interval.
As authors you may consider using insects as a testing source for drugs or toxins, especially when other tissues are not viable. Consider too the absence of certain prescribed drugs that may affect the victim’s behavior or general health. The drugs may be illegal or they may have been stolen by the suspect from another family member, friend, or co-worker. The presence or absence of drugs or toxins may also reveal a “unique” data point in the unidentified victim’s profile to compare against missing person’s records, medical records, or even criminal modus operandi (such as the use of a date rape drug or poisoning by mercury). You probably already have an interesting application of drugs or toxins in your storyline. The use of insects to test for those substances will provide for some interesting dialog between characters or plot twists for your readers.
The art of observation is critical to every CSI. We have to be able to see things that others can not. Contrary to popular opinion we don’t always “see” everything that we see. To steal an example from Sir Arthur Conan Doyle; close your eyes and say out loud how many steps it takes to get from your bedroom door to your kitchen. Easy right? I mean, you probably walk that route several times a day don’t you? Why would you have trouble describing the number of steps it takes? It’s the difference between “seeing” and “observing”. We may see things but we may not observe them.
As authors, we have to describe scenes for our readers. We have to do it in such a way that they feel a part of the scene. This is easier when we feel a part of it ourselves. I’m sure you’d agree that your writing is much better when you’re describing a place you’ve actually visited. But even if you’re familiar with the setting…how well do you really know it? Here is a simple exercise to help you develop your skills of observation. The more you practice such exercises the more vivid and detailed your scene writing will likely become.
Where ever you are right now, get a sheet of paper and a pen. Pick a room on the other side of your home (or your office). Imagine yourself standing in the doorway facing into the space. Now I want you to describe the room. Start on your left and begin writing down everything I would see if I were standing where you are. Spare no detail. Give yourself ten minutes to complete the task. Then try to draw a “birds-eye” diagram of the furniture in that space. When you’re done, take the notes and diagram to the room and see how you did. Did you capture all the detail? The colors…the sounds…the smells?
If you live in a dorm room or one bedroom apartment you can try something a little different. Think of a picture in your place of employment or relatives house. Got it? Now describe it and draw it. What are the colors? How many elements (people, animals, buildings, etc.) are in it? What color is the mat board? How about the frame? Where is it on the wall?
I’m not suggesting that CSIs have photographic memories. We don’t observe everything either but, we develop our skills of observation to “see” more than the average person. I’m betting that, as authors, you see more than you think; more than most others. Exercises like this are what we use to train new CSIs to observe details others may miss. I hope that you’ll find it an interesting first step in enhancing your observation skills.
Dr. Jane Bock is a forensic botanist and researcher from Colorado affiliated with a number of professional organizations. She has been conducting field research for over four decades and has received numerous awards including the Ralph W. Schreiber conservation award and Hazel Barnes Prize. I first met Dr. Bock while working in NecroSearch International. She has worked numerous murder cases across the nation and is very approachable for those seeking additional information. The field of forensic botany is fascinating. From looking at last meal evidence to disturbances from burial, plant material can provide great insight to an investigation. If you’ve never thought of including botanical evidence in one of your novels you might reconsider after reading this interview. Her new book Handbook of Forensic Botany will be released this year.
F4F: Historically, how long have plants been used in forensic investigations?
BOCK: Forensic botany reaches far back in Western history. Plato, in his writing (Phaedo 399 BCE), describes the suicide of his teacher, Socrates, in detail. Socrates chose to commit suicide by imbibing poison hemlock (Conium maculatum). Plato’s description of Socrates’ symptoms fits exactly the pattern of poison hemlock poisoning today in the US and Europe. Forensic botany became ‘scientific’ with the inventions of the printing press (1440 AD) and the light microscope lenses (1590 AD). Using a microscopic lens, Robert Hooke described the cellular nature of cork cells, later published in his book, Micrographia. The earliest books describing plant cell types followed shortly. Forensic botany came of age in the US in 1934 when botanical evidence was used to solve the kidnapping and murder of Charles Lindbergh’s baby boy.
Botanical evidence in courts today is accepted readily through both Frye and Dauburt examinations provided the witness shows competence in botanical knowledge. My cases have involved knowledge from three subdivisions of botany: plant anatomy, plant taxonomy, and plant ecology.
F4F: How are plants used in last meal evidence analysis?
BOCK: Dr. David O. Norris and I fostered the identification of food plant cells in criminal investigations and trials. Plant cells usually are enclosed in cellulose walls. These complex carbohydrate walls are virtually indestructible. They pass through the human digestive tract unchanged in their sizes and shapes. It does not matter if the plant was consumed raw, canned, frozen or cooked. Each food plant has cells that are distinctive in size and shape. We commonly examine plant cells from stomach contents. There is a rough time table for how long each stage of the human digestive process takes, and the time for stomach digestion usually is within a couple hours of consumption, then the material passes to the small intestine. This can be helpful in some homicides in estimating the time of death.
Identifying food plant cells from the digestive tract and feces of a homicide victim may link the victim to a certain place where a meal was taken and may link a suspect’s presence to that same place. Two recent cases involved the plant foods found in the stomach contents of people whose exact diets were known (hospital and prison). When the records of the day’s meals were compared with stomach contents, we learned which meal was the victim’s last even though a suspect claimed the person had been killed after a later meal.
F4F: What are the most common types of analysis you’re asked to conduct for law enforcement?
BOCK: Plant Taxonomy: assigning the correct scientific plant name to a plant or plant fragment. Such identification can link a victim to a suspect through plant fragments found in clothes or vehicles. Such evidence also can show a place where a victim and/or suspect visited. what residences These cases are relatively common. Plant Ecology: the relationship between plants and their environments. Here, you test ideas about where plant materials originated. In a case, a truck contained fragments from a mountain setting, but the trucker claimed the vehicle never had left the prairie. This along with other evidence led to a murder conviction.
F4F: Some of the readers may be unaware of the use of pollen, seeds, and diatoms in forensic investigations. Can you talk a little about how they may be used to link a suspect to a crime scene?
BOCK: Most plants are made up of stems, roots, and leaves, plus reproductive parts (flower parts and seeds). These all have cellulose cell walls. However, other organisms have cell walls comprised of other substances. These plant structures can fall into the forensic botanist’s purview, and include pollen, spores, and certain microorganisms. The presence of pollen in association with a cold case homicide can suggest a season when a crime took place because the shedding of pollen is highly seasonal. Diatoms have cell walls of silica and are virtually universal in all bodies of water from mud puddles to oceans. However, species distribution and relative abundances among species have given strong evidence of the source the water in a case. Here, the water in the victim’s lungs indicated that he had been in a body of water that was distinctive from the location described by the suspect.
F4F: You’ve been involved with a number of high profile murder cases over the years. Is there any one case involving plant evidence that really stands out to you and why?
BOCK: High profile cases can be difficult if the media have publicized widely their decision about guilt. For example, in the defense for the Casey Anthony case, making trips to the courthouse involved running a gauntlet of reporters and other supporters of a guilty verdict yelling my name. Also, e-mail threats for the expert if you are involved with the ‘unpopular’ side. The most renowned high profile murder case I’ve worked occurred over 10 years ago and has not been brought to trial. Therefore, it is an ongoing case and my evidence cannot be discussed here. This continues to weigh heavily on me because of what my partner and I know from our evidence. In a recent cold case in Pennsylvania where the victim was an 80-year old woman, we determined the contents her last meal. It had served as the medium for the poison that killed her. We supplied a deposition and this led to a confession of the persons who killed her. Had it gone to trial it would have been very high profile.
F4F: What’s on the horizon in forensic botany? Are there new technologies that are poised to open areas of inquiry that were previously unknown?
BOCK: A worrisome aspect of this field is that it is underutilized and under represented. The approaches described above are simple, inexpensive, and readily accepted in courts. Many more people with forensic interests must train themselves in botany. DNA can be useful in forensic botany, but our lab does not deal with it. It is not especially useful in plant identifications because there are at least 300,000 plant species., and most of their DNA patterns are not known. What DNA can do is link plant fragments from a single plant to a suspect to a victim, to a vehicle, to a place. This works well. DNA analysis is being streamlined and will become more so. Already some kits are showing up so that a major laboratory may not be required.
I am happy to discuss forensic botany with interested individuals, and also to point them to appropriate scientific literature.
Blood evidence is a powerful tool for the crime scene investigator. Whether testing for DNA or examining the bloodstain patterns to reconstruct the events of a crime blood is a powerful witness. This fact is not lost on the criminal. This knowledge is rooted in the old saying “caught red-handed” in which a criminal with blood on his hands was thought to be guilty. So criminals have learned to clean crime scenes and evidence and CSIs have learned ways to recover it. Without getting too deep in the forensic weeds; cleaning efforts usually result in either diluting the blood or masking it. Using a washing machine is an effective way of diluting bloodstained clothing. Criminals also have easy access to washing machines so it’s not too surprising that they may utilize them to wash away evidence.
Some of you may already be asking “why not just throw the clothing away?” It’s a god question but to understand it you have to understand a criminal and what they value. A t-shirt may get thrown away like garbage but if the item is their favorite jacket, sports jersey, athletic shoe, or ball cap then they may just roll the dice. One key thing to remember about all criminals. They will clean a crime scene to a point they do not see the evidence. That doesn’t mean the evidence is gone, it’s just beyond the abilities of the criminal to see it. So…will washing clothes destroy blood evidence? Sort of.
I won’t reveal the current state of DNA detection, suffice it to say that researchers are making breakthrough’s all the time. I’ve written before about the durability of DNA evidence and some of the current case studies and research might blow your mind. On the matter of dilution there are some amazing reagents like Luminol that may detect blood at one part per million. Several years ago I conducted a study to see if we could detect bloodstain patterns on washed clothing. I didn’t have high hopes but I thought it may be possible. The long of the short is that a number of cotton shirts were stained with various bloodstain patterns and then subjected to a series of alternating wash and dry cycles. I used washing detergent with bleach and dried the items in a hot-air clothes dryer. The long of the short is that I was able to detect blood on the clothing after five alternating cycles of washing and drying. At the time I used horse blood and DNA testing wasn’t as inexpensive as it is today so I didn’t address that issue. I just wanted to see if the bloodstain patterns could be detected.
You may want to keep this in mind as you’re developing your story. If your bad guy washes his/her clothing you may want o have your good guy find it. This would also work with victim’s clothing that has been exposed to rain, submersion, etc. If you develop a DNA profile all the better! I certainly won’t criticize you for it.
Footwear impressions can provide valuable information to the crime scene reconstructionist. Examiners look for class and individual characteristics in crime scene shoe impressions that may link that impression to a particular suspect shoe. In order tom compare a crime scene shoe print to a shoe though, it’s best to make an impression from the suspect shoe. There are a number of ways to take footwear impressions. One can use black ink or fingerprint powder but, a novel method is the use of an inkless pad. The process involves a pad coated with a special “ink” and chemically treated sheets of paper large enough to hold a boot impression. They work great for footprints as well (no one has yet developed one for taking tire impressions). The ink pad is generally yellow in color, odorless, and can be used for several hundred impressions before it needs replacement. You have to use the chemically treated paper however. The process will not work with standard bond paper because of the chemical treatment. The paper isn’t cheap either. A pack of one hundred sheets costs about forty dollars (US). Initially, the inked impression may appear green in color but will dry black. This provides the highest contrast with the white paper.
This process is well suited for taking elimination impressions. Elimination prints are those from people who may have been in the crime scene but are not suspects. This includes victims, family, customers, employees, etc. The inkless method means you don’t make a mess of everyone’s shoes or run the risk of them tracking traditional ink or fingerprint powder all over the crime scene. It also means you can take very good impressions without having to collect the shoes. Now occasionally, a victim will be wearing shoes very similar to the suspect. In such cases the CSI will have to collect the shoes and book them in as evidence unless they are easily distinguished in size. For everyone else though, this inkless method works very well. All of this is in addition to photography of course. You might be asking yourself…why take impressions if you’re taking photographs? The simple reason is that an impression is a full scale representation of the outsole. Photographs may be slightly out of focus or at an odd angle so that when you enlarge them to life size they do not align correctly. The link below is to a short video demonstrating this process. The only thing I would add is that it is better to wear the shoe and step onto the pad. The weight of the body imparts a better impression in my opinion.