Blog Archives

Using Luminol to Detect Blood on Concrete Nearly a Year After Deposition

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.

Using Your Smart Phone for Metal Detection

Searching a stream with a modern metal detector

Searching a stream with a modern metal detector

First, let me apologize for being absent of late. Between promoting my new novel Bloodlines and writing the third book of the trilogy I’ve been neck deep in projects. I’m also trying to get my annual snow casting class put together and research as well. Plus it’s summer and what can I say…

I came across a little smart phone app a while ago that could make for an interesting scene in your novel. Did you know that your smart phone could be used as a metal detector? You see, modern phones have a magnetic sensor used primarily for navigation. But with a little tweaking that same sensor can be used to detect ferrous metals. There are dozens of apps available for both Apple and Android products. One I like is from Phase 2 Media. These apps are geared for the weekend treasure hunter or beach comber but they could come in very handy for your character.

Most CSIs have access to high quality metal detectors rated for both terrestrial and aquatic use.  In fact, metal detectors were born from a need to find forensic evidence.  That’s all well and good but sometimes CSIs aren’t available. With this app a private detective, security guard, soccer mom, or adventurous baby sitter can tap into the same technology to find a crucial clue! How cool is that! Now these phone sensors have limitations. You won’t find a gun buried in ten feet of clay soil but you could find one buried in a few inches. Your character could even use this app to sweep a person for a hidden weapon (just like a security guard does). Or maybe they vacuum seal their phone in a plastic food bag and use it underwater (I wouldn’t try this in real life :)).

The possibilities for this technology are limited only by your imagination. Whether writing a police procedural or a cozy your characters can wow their “peers” and your readers with this high tech app. If you already have a scene using a metal detector, consider rewriting it to include this app. There may be some kind of hurdle that dooms the case until your character overcomes the problem by downloading the app.  If you have a smart phone read the reviews and try playing with one in your yard or better yet…at the beach!

For those who have submitted questions bear with me. I will get to you soon. If you haven’t had a chance to check out Bloodlines watch the trailer below. To those who have purchased it, my deepest thanks!

Ever Wondered if an AK-47 Will Fire Underwater?

I’m a sucker for these types of videos and I figured a few of you might be too.  Some people question whether a gun will fire under water and what the effects might be.  As you’ll see in the below video, the gases released during discharge react differently in water than they do in air but the video does give you some idea of where and how the gases and GSR are expelled from the firearm. Obviously you could never recover GSR from a suspect firing a gun under water but the video is neat nonetheless. I thought it was especially interesting to see the cycling of the weapon was faster under water than in air too. Enjoy.

Laser Mapping a Crime Scene

Leica_ScanStation_P20_PIC_180x180I 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!

Stringing Bloodstains: The Old School Method

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.

Interview on Written Dreams Today

My Bloodlines editor Brittiany Koren has posted an interview with me on her blog today. Please stop by and visit. If you’re looking for an editor I highly recommend her. She is diligent, patient, and very professional (not to mention reasonable in price!). Her blog is a must read. She’s got great tips and insight I’ve found invaluable.

Introducing the M-Vac DNA Vacuum

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.

In Defense of Police Dispatchers

Okay, this is not really a forensic topic but recently I’ve been hearing some criticism of police dispatchers and since I am friends with several of them I thought I’d take a moment to comment on the position. In The Scent of Fear, one of my second tier characters is a dispatcher and friend of my heroine Sarah Richards. The dispatcher in the Amanda Berry case made national news (perhaps international) after taking the call from the kidnapped victim in Cleveland, Ohio. While I’m not going to share my opinion on that call I will address some of the common complaints levied at dispatchers from some in the public. Folks that don’t listen to dispatchers on a daily basis often believe dispatchers are dispassionate, even disinterested in the events coming through their headsets. While there are certainly unprofessional dispatchers out there, my experience with them has been good. It’s a tough job. You have to handle everything from the absurd (calling 911 to complain that their fast food order is wrong), to the crazy (my dog is an alien sent to spy on me), to the most stressful calls you can imagine like officer (read: friend) down or instructing an eight-year-old on CPR for their dying mother. That’s just a Tuesday in some jurisdictions mind you. It takes a special kind of professional.

I remember one time sitting in my office listening to the police radio when an active shooter began his rampage in his neighborhood. The part I remember most was hearing my friend on the SWAT team being pinned down and taking fire. Bullets were tearing through the wall just above his head and there was nothing I could do but listen. I prayed to hear his voice again through the static and thankfully he came out of it all uninjured. The other thing I remembered was how calm the dispatcher was in relaying the information to other responders. She was also his friend and I suspect she felt many of the emotions I did. She was just better at handling them than I was.  If you think about it; a dispatcher that looses it over a stressful call wouldn’t be very helpful to the officers that need him or her to multi-task the various tasks they need to do in order to support patrol operations. What sounds to some like a lack of concern or recognition of the severity of the situation is often just the dispatcher being the professional they’re required to be.

Another common complaint I see if that the dispatcher asks too many questions. “Shut up and send the officers!” “Quit asking so many stupid questions!” Have you ever thought that while listening to a radio dispatch on the news? The truth is that dispatchers can handle multiple duties at once. They can alert and dispatch officers over their mobile data stations (computers) while talking to the victim on the phone. Other dispatchers in the call center can also monitor the call and may be dispatching additional units, fire, ambulance, etc. They just aren’t talking on the same line so you never hear that portion of the call.  Handling such calls takes concentration but that’s what they are trained to do. They have to go through a selection process in the same way officers do and the ones that can’t handle stressful multi-tasking often don’t get the job.

The video below is a nice tribute to one of the most thankless jobs in law enforcement. If you are writing a dispatch character you might want to consider how their job affects their personality. How they handle stress and how they communicate with those around them. Dispatchers can form a tight bond with the officers they work with and may know those officers better than the watch commander.

What the Heck is Entomotoxicology?

The House fly

The House fly

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.

An Experiment in Observation

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.


Get every new post delivered to your Inbox.

Join 375 other followers

%d bloggers like this: