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.
Today I thought I’d cover a interesting fingerprint reagent called R.A.M. RAM is a mixture of three fairly common fingerprint reagents; Rhodamine 6G (R6G), Ardrox, and MBD 7-(P-Methoxybenzlamino-4Notrobenz-2-Oxa-1,3-Diazole). To my knowledge this reagent gained popularity in the early 1990′s and continues to see use today in many crime labs. These reagents are used to enhance fingerprints developed through superglue fuming (cyanoacrylate) followed by inspection under ultra-violet light. All three of the above reagents comprising this mixture are used in fingerprint development so one might wonder; why mix them? Simply put, the mixture can create a broader range and intensity of reactions making photography much easier. Of course, that was more of a concern when lasers and light sources had weaker light output (100w) compared to the units today putting out 500w. Fluorescent dye stains are very practical when processing fingerprints on multicolored non-porous surfaces because the colors of the background surface are muted under ultra-violet light and the fingerprint reagent stands out under fluorescence.
Once the evidence is fumed, the RAM can be sprayed or applied with a squirt bottle. The item can also be dipped in a tray of reagent. There is no need to rinse the item after processing with RAM. The RAM reagent is a yellow color and a little thicker than water in viscosity. Once the item is dried it is examined under ultra-violet light between 415nm and 485nm with the best results usually found at 460nm with an orange colored barrier filter. The shelf life of RAM is approximately thirty days or until certain components like petroleum ether begin to separate and will not reconstitute.
I’ve written before about the three types of crime scene photographs. Well, those photos are the ones taken at ground level. Photography is all about perspective and sometimes you need to get off the ground. Most of you are probably aware of aerial photographs taken from rotary or fixed wing aircraft. I’ll post something on historic and modern aerial photography soon but there is a simpler and more widely used practice to obtain a heightened perspective. We call it elevated photography. There are a number of ways to obtain an elevated perspective. All of them are dependent on the conditions on scene and the available equipment. Of course, these techniques can also be used in the crime lab to photograph large items like bedsheets or large areas of carpet. Here are a few examples.
This is a simple product marketed for crime scene investigators. Basically it’s a pole with an attachment for the camera. Fancier models also include a shutter release cable to trip the camera and take a picture. The best results require the operator to manually focus the camera lens. Since the operator can’t see through the view finder you usually have to make several test shots to achieve the one you want. These booms are typically employed in places like bathrooms or bedrooms where there is limited space or height to elevate the photographer. They can also be used to photograph objects in elevated positions like bird nests or tree limbs.
The simplest is a six foot bi-fold ladder. A CSI may also use scaffolding or a taller ladder. In the extreme you might use a fire truck ladder extended out over a body or vehicle in a field. Of course, the higher you go the more risk you’re exposed to. I remember the first time I went up on a fire truck ladder. I was taking pictures of a woman’s body that was dumped in a field. There was no harness and pretty strong winds. I was pretty scared. It seemed to take hours and I couldn’t bring myself to get more than forty or fifty feet in the air. These days, safety is taken more seriously and after a few trips up you get used to it. Of course, if you hate heights you may have to call in a favor from a co-worker to take your place.
An Elevated Platform:
Any elevated position can work as well as a ladder. It may be the landing above a living room or the rooftop of an adjacent building. Some larger crime lab vans also have special roof platforms designed to accommodate a photographer. Fixed locations obviously limit the options for the photographer but they may be better than nothing.
Today I have a real treat for the readers of F4F. New York Times Best Selling Author Laura Grffin has agreed to discuss her career, characters, and her new novel Scorched which just hit bookstores. Laura likes to mix forensic scientists with Special Operations soldiers so naturally, I’m a HUGE fan! If you haven’t picked up one of her books you don’t know what you’re missing.Laura also has a cool forensics quiz on her website. Take a look and see how you score!
Laura started her career in journalism before venturing into the world of romantic suspense. Her acclaimed novels have won various awards, including both a RITA Award for Whisper of Warning and a Daphne du Maurier Award for Untraceable in 2010. Her debut novel, One Last Breath, won the Booksellers Best Award in the Romantic Suspense category, and her novels Snapped, Unspeakable, and Untraceable were all nominated for Reviewers’ Choice Awards by RT Book Reviews magazine.
F4F: You’ve written a number of Romantic Suspense series but each Tracer novel seems to dive a little deeper into forensics. How did you start researching the forensic sciences?
LG: Thanks for having me today, Tom! I love reading Forensics4Fiction.
My interest in forensics started with a forensic artist. I was interviewing her for a book and she started telling me about doing postmortem drawings to help identify unknown victims. That interview made me realize how many people—besides the detectives—work behind the scenes to solve a case. I started interviewing CSIs, forensic anthropologists, fingerprint specialists, firearms experts, basically anyone who would talk to me about what they do.
F4F: You’ve created the Delphi Center crime lab which is almost a character in its own right (I know I’d like to work there). Did you have to visit any working crime labs to inspire you?
LG: I’ve visited a number of different crime labs to gather info and details. The labs themselves are interesting (it’s fun to see all the high-tech equipment) but what really brings them to life the people who work there. I love to hear people’s war stories and learn how they got involved in police work. When I visit a lab, each person is a treasure trove of story and character ideas.
F4F: You were a seasoned journalist before becoming a novelist but the underworld of crime can be quite disturbing. Is there anything you find particularly difficult to write about?
LG: One of the toughest assignments I ever had was a child kidnapping that ultimately became a murder investigation. It was heart-wrenching to talk to the parents in that case, and as a young reporter I found it hard to stay objective. You can’t just turn your feelings off like a faucet. Some of the emotions I felt while covering that story became part of my heroine’s character in THREAD OF FEAR, which opens with a child abduction.
F4F: Your latest book SCORCHED features a forensic anthropologist named Kelsey Quinn. Forensic anthropologists are an interesting lot and Kelsey has a lot of turmoil in her life. What inspired you to choose that profession for her?
LG: Basically, I’m fascinated by bones. I took some anthropology classes in college and I was amazed at how much you can learn about a culture by looking at bones and artifacts. To me, forensic anthropology is even more interesting because you have this added challenge of searching for clues to solve a crime. How did this person die? What do the bones reveal about the sort of life they had? How can the bones help track down the killer?
F4F: SCORCHED also features a body farm. I’ve done research at a body farm since the mid 90′s and it’s a special place. There aren’t many around but have you been to a body farm? What were your impressions?
LG: The body farm here in central Texas was the original inspiration behind the Delphi Center. I have been to visit and was extremely impressed with the people working there. The (fictional) Delphi Center from my books is both a body farm and a crime lab, which gives me lots of story options. Delphi is home to an elite group of investigators, known as Tracers, who specialize in all areas of forensic science. So I’ve got lots of experts at my fingertips whenever I need a new character or a plot twist.
F4F: One of your characters (Gage Brewer) is a USN SEAL, The SOF community is notoriously shy. Has it been difficult to shape this character?
LG: Yes, they are shy! When I was first trying to interview a SEAL he kept putting me off and putting me off. Just when I was about to give up and start looking for someone else, he got in touch and told me sorry to keep me waiting, but he’d been sidetracked in Afghanistan, and could I please re-send the interview questions. Besides talking to a few SEALs, I learned a great deal from books and documentaries, and these men are simply amazing. I enjoy writing SEAL characters because really there is no challenge too daunting. SEALs will find a way, no matter what.
F4F: I can’t get away without asking you about your writing process. Some writers plot out every scene in advance on complex organizational charts. Others write organically. How would you describe your process?
LG: I’m always envious of writers who describe a smooth process. For me, it’s a mixed bag. I do a lot of planning for my characters. I research their professions, try to get to know them. As for plot, I usually start with a basic plan, but it takes turns and detours and often looks nothing like I envisioned originally. Somehow it works out, though. I don’t like to get too hung up on a specific path because the surprises are the fun part.
F4F: Tell the readers something about yourself they can’t get from your website.
LG: Hmm…I don’t know if my website mentions that I’m a huge book addict. My office contains everything from chick lit to books on abnormal psychology, medical journals, firearms guides. Oh, and I’m a chocolate addict, too. Open a desk drawer and you’ll probably find something sweet.
F4F: Thank you so much for sharing your time with us Laura. If any of you readers have a question or comment for Laura she’ll be checking the comments section. If you haven’t picked up one of her books…what are you waiting for?!?
The dead don’t speak, but Kelsey knows their secrets. As a forensic anthropologist at the Delphi Center crime lab, Kelsey makes it her mission to identify bodies, often using no more than shards of bone. Her find at a remote Philippines dig hints at a sinister story. When Kelsey’s search for answers puts her at the scene of her ex-fiancé’s murder, only one man can help her–the man who broke her heart months before and is also a prime suspect.
Faced with an ultimatum—Kelsey or his job—Gage Brewer did the only thing a Navy SEAL could . . . but that doesn’t mean he stopped wanting Kelsey. Now Kelsey is running for her life and Gage is her last line of defense.
In the last installment I wrote about the call out procedure for the criminalist. Once the CSI arrives on scene though, then what? I’m glad you asked! We begin by finding the first responder(s) on scene. This is usually an officer or deputy but sometimes a detective may be there already too. Before we break out the slide rulers, lasers, and whatchamacallits we have to find out what is going on. Believe it or not, we don’t always get the complete picture from the initial call out. Sometimes it’s kind of funny (lie the time I got called out on a suspicious death…of a bird!) other times it can cause a lot of arguing. So when we arrive we need to do a walk thru. Basically, the officer will take us a tour of the scene and tell us what they know about it. We want to know certain things like,
- Were any statements made when the officer arrived?
- Was anything moved (officers may need to unload a firearm before we arrive)?
- Did the officer make any alterations (turning on/off lights, opening doors or windows, changing thermostat, etc.)
- What has the officer touched?
- Were there any sounds or smells no longer present?
We also need to get an idea of what we’re about to get into. Are there any hazards on scene? This can be anything from a vicious dog to dirty needles. There may be significant distractions like alarms, distressed family members or irate property owners, or even bad guys hiding somewhere inside. We also assess the types and amount of evidence we need to collect. For example, if we need to collect a couch, bed, or section of wall we’re going to need more help. We may need specialized equipment like an alternate light source, total station, infra-red camera, or simply more criminalists. We may take notes and photographs during the walk-thru but we don’t collect or process any evidence.
The walk thru is a great opportunity to plan how you’ll process the scene. What will you process first, second, and so on. Are there certain items that require immediate attention? Some believe that the dead body takes priority but it may be less vulnerable than a suspect shoe print in the snow outside. The walk thru is the best way to make these decisions. It is also an opportunity to “test” any statements made by first responders or witnesses. An officer may believe a death to be natural but if you see an open pill bottle in the trash it may indicate suicide. Officers are trained to disturb only what they have to to secure the scene and tend to victims. As such, they usually have an incomplete picture of the events but that’s to be expected.
As a writer you can use the walk thru to change the direction of the story or test the characters. The call may come in as a suicide but may in fact be a homicide. Gullible or lazy CSIs might accept the things they are told by first responders instead of questioning them in more detail. This can have disastrous effects. You rarely get two chances to process a crime scene. The challenge is to get it right the first time. The best way to begin on a solid footing is to do a thorough walk thru.