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Category Archives: General Forensics

Holmes, Thorndyke, Locard, Gross, and the Modern CSI

There are no bigger names in the history and development of modern crime scene investigation than French investigator Edmond Locard and his Austrian counterpart Hans Gross. These two men shaped the development of crime scene investigation and even today their techniques create the cornerstone of forensic science. Locard’s Exchange Principle underlies every forensic technique.

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EDMOND LOCARD

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HANS GROSS

They were also great fans of Sir Arthur Conan Doyle’s Sherlock Holmes and R. Austin Freeman’s Dr. John Evelyn Thorndyke. Locard even suggested that students of police procedure read the Sherlock Holmes stories and learn from his techniques.

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Both the real-life investigators and the fictional ones had one thing in common: the careful and meticulous approach to any crime scene, taking care to collect all useful evidence, while not damaging or contaminating it.

In my book Forensics For Dummies, the methods and techniques used to evaluate a crime scene and collect evidence are explained in great detail. Check it out if you want to know more about the techniques that saw their origin more than 100 years ago.

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Luminol and A Malarial Drug Team Up to Find Hidden Blood

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Sometimes blood shed at a crime scene is easily visible but at other times less so. Maybe it’s a very small amount, or perhaps soaked into a patterned carpet, or secreted in the gaps between tiles and baseboards. Perhaps the killer has cleaned up the crime scene, thinking that if the blood is not visible, it’s not findable. Maybe he even washed the blood off is hands and watched it circle down the drain. Gone forever.

Or maybe not. Things such as luminol can uncover these hidden stains.

Luminol is actually quite sensitive for finding blood. Spraying it on a wall that has been wiped clean of visible blood, or often even if painted over, and then turning out the lights will reveal the glowing pattern of the blood splatter. This helps not only to locate the blood but also to identify patterns, which, in turn, might help re-create the crime scene. Such reconstructions are critical in bloody homicide investigations.

From FORENSICS FOR DUMMIES:

Reconstructing the crime scene from bloodstains 

Contaminated evidence is no evidence at all, so investigators have to document bloodstain and spatter patterns in a timely and logical fashion. Police, fire, and rescue personnel can alter or contaminate the blood evidence, as can any unnecessary foot traffic at the crime scene. For that reason, investigators need to take control of the scene immediately and consistently. 

Unless they’re high‐traffic public places, indoor scenes usually can be preserved long enough for investigators to obtain needed information. Outdoor scenes, however, are subject to environmental influences, and public places require investigators to gather information more urgently. 

Investigators carefully photograph bloodstains. Initial photographs capture an overall view of the scene. Subsequent pictures gradually move in on individual stains. The photographer takes pictures of individual stains close enough to reveal all needed detail, and should include a ruler or other measuring device to provide a scale reference. In homicide cases, investigators check out the body and any associated bloodstains or spatter first. After the body is removed, investigators turn their attention to other spatters. 

Some bloodstains are latent (invisible to the naked eye). Investigators often use luminol to expose these hidden stains. Luminol is a chemical that reacts with the hemoglobin in blood to produce a complex substance that luminesces (glows). Luminol is extremely sensitive, detecting blood in concentrations as low as one part per million. Investigators darken the room and spray luminol over areas where they suspect blood to be. When blood is present, stains glow a bluish‐white, and the photographer takes pictures of the glowing pattern. 

Luminol also can reveal bloody tracks that indicate the perpetrator’s movements or escape route and drag marks that show whether anyone moved the body. Luminol is so sensitive that it can uncover blood in cracks, crevices, and even areas where someone has tried to clean it. 

It’s important to note that many substances can interfere with or confuse luminol pattern analysis. Bleach and other cleaning agents, certain paints and varnishes, and even some fruit juices are examples. 

After photographers take an adequate number and variety of photographs, crime‐scene analysts complete their analyses and create a report that may include implications of the victim’s and assailant’s locations at each stage of the crime, the number and types of injuries inflicted, and the exact sequence of events (see the next section to understand how analysts gather this information).

But, as mentioned above, there are things that interfere with this chemical process. Certain fruit juices, bleaches, horseradish and turnips, and other chemicals will also react with luminol and this can confuse the issue.

A recent study reported in Science Daily suggests that a new method might help solve some of these problems. Combining luminol with the antimalarial drug Artemisinin seems to reduce this cross-reactivity and therefore more specifically display the true blood spatter pattern. Obviously, more research is needed, but this is a potentially useful tool.

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Webinar: What Were They Thinking? The Planning of the Perfect Murder

Join me for a fun Webinar hosted by Sister in Crime-Atlanta on Tuesday, June 13, 2017 from 7:00 to 8:30 p.m. Eastern Time. You must be a member of that chapter to join is but if you’re already a SinC National member it’s only $20.

Here is the info on the event:

When your character plans and executes “The Perfect Murder,” he always, ALWAYS makes a mistake or two. These errors ultimately lead your sleuth to the solution. In this session, Dr. D.P. Lyle deconstructs the planning, execution, and post-crime behavior of two headline-grabbing murderers–O.J. Simpson and Scott Peterson—to help mystery writers and fans better understand fictional killers from social, psychological, forensics, investigative, and motivational points of view. Q & A follows a 1-hour presentation. Forensic questions welcome!

Webinar: https://www.meetup.com/Sisters-in-Crime-Atlanta-Chapter/events/239240813/

SinC-Atlanta: https://www.sincatlanta.com

 

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Can Your Pacemaker Snitch On You?

Don’t you just hate it when your pacemaker snitches on you? I mean, apparently all you wanted to do was burn down your house and collect the insurance money but then your pacemaker spoke up. Your plans went up in smoke – – no pun intended.

Pacemakers surely have changed since I was in medical school. Back then, they had to be inserted in the abdomen and the pacemaker leads shoved up through the diaphragm where they were screwed into the heart muscle. It was a major procedure, done under general anesthesia. The device weighed around a pound and only lasted 12 to 18 months. Then you had the pleasure of doing it all over again.

Also, back then, pacemakers were mostly a safety net. They were used for people who had very slow heart rates, even episodically, to prevent dramatic drops in the heart rate that could lead to dizziness, falls, and loss of consciousness. Pacemakers were often set at 60 to 70 beats per minute which meant that your heart rate could never fall below that. The pacemaker would sit and watch the rhythm and any time the rate dropped below these parameters, the pacemaker would kick in and supply the electrical impulse the heart needed.

Things are much different now. Today’s pacemakers are small, about the size of a wristwatch in many cases, last a decade or more, and will do much more than simply provide a safety net. They can help regularize abnormal rhythms, increase heart rate in response to exercise, and do a myriad other things to make them more efficient and helpful.

They also store data. This means that the pacemaker can periodically be interrogated and everything that has gone on in the individual’s rhythm over the past few months is available for analysis. And some of the newer models actually send the data to a central monitoring station in real time. My how things have changed.

For Ross Compton, his pacemaker, which was of course equipped with all this new technology, just might have snitched on him. According to investigators, Compton allegedly torched his house, likely in an insurance scam. He said that once he saw the fire he began unloading his most important belongings out a window and ferried them to his car. It was a real fire drill of sorts.

However, when his pacemaker was interrogated it showed no changes that would be consistent with such frenetic activity. No arrhythmias, no high heart rates, nothing to suggest extreme physical activity during the time in question. Had he actually been lugging stuff out the window and racing to his car one would expect that his heart rate would be greatly elevated from the exertion. Apparently, that’s not what was found.

It’s going to be interesting to see how this case turns out.

 

Crime and Science Radio: Facial Recognition and Other Biometrics with FBI Senior Photographic Technologist Richard W. Vorder Bruegge

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BIO: Richard W. Vorder Bruegge is a Senior Photographic Technologist at the Federal Bureau of Investigation where he is responsible for overseeing science and technology developments in the imaging sciences.  He has an Sc.B. in Engineering, and an Sc.M. and Ph.D. in Geological Sciences from Brown University. He has been with the FBI since 1995, where he has performed forensic analysis of image and video evidence, testifying in state, federal and international courts as an expert witness over 60 times.  Dr. Vorder Bruegge was chair of the Scientific Working Group on Imaging Technology (SWGIT) from 2000 to 2006 and chair of the Facial Identification Scientific Working Group (FISWG) from 2009 to the present.  He is a fellow of the American Academy of Forensic Sciences (AAFS) in the Digital and Multimedia Sciences Section.  In 2010 he was named a Director of National Intelligence (DNI) Science and Technology Fellow for his work in facial recognition.  He is currently Chair of the Digital/Multimedia Scientific Area Committee in the Organization of Scientific Area Committees (OSAC).

LISTEN: http://www.blogtalkradio.com/suspensemagazine/2017/04/01/crime-and-science-radio-with-special-guest-richard-bruegge

Link will go live Saturday 4-1–17 at 10 a.m. Pacific

LINKS:

Biometric Center For Excellence (BCOE): https://www.fbi.gov/services/cjis/fingerprints-and-other-biometrics/biometric-center-of-excellence/modalities

Facial Identification Scientific Working Group (FISWG): https://www.fiswg.org

FBI Caught On Camera: https://www.youtube.com/watch?v=u5Oj2FDwLXs

 

Q&A with Expanded Audio Discussions Now on the Suspense Magazine Website

Q&A with Expanded Audio Discussions Now on the Suspense Magazine Website

Check out the new posts John Raab of Suspense Magazine and I put together. Read the Q&As and listen to the expanded discussions. Hope each proves helpful for your crime fiction.

Can DNA Be Used To Identify Multiple Assailants In a Three Decade Old Rape?

http://suspensemagazine.com/blog2/2016/12/20/d-p-lyles-forensic-file-episode-1/

In 1863, Could An Autopsy Accurately Determine the Cause of Death?

http://suspensemagazine.com/blog2/2017/01/09/in-1863-could-an-autopsy-accurately-determine-the-cause-of-death-d-p-lyle-answers-this/

Can My Female Character Cause Her Pregnancy To Become “Stone Baby” By Shear Will?

http://suspensemagazine.com/blog2/2016/12/31/can-my-female-character-cause-her-pregnancy-to-become-stone-baby-by-sheer-will/

More to come.

Want more cool questions from crime writers? Check out my three Q&A books.

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More Info and List of Included Questions

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More Info and List of Included Questions

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More Info and List of Included Questions

 

Guest Blogger: Lisa Black: Smart Phones and Not-So-Smart Criminals

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USING SMARTPHONES TO DEFEAT NOT-SO-SMART CRIMINALS

My boss, the supervisor of our forensic unit, insists that soon we will be able to process an entire crime scene with nothing but a smartphone. Everything from photographs to sketching to measuring to note-taking, all on a 2 ½ x 5” flat item which one needs reading glasses to see unless one is under fifty which I, alas, will never be again.

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Most phones now come with 10 or 12 megapixel cameras, which are more than sufficient for forensic purposes. You can get attachments for tripods and flashes. My boss can open and close the shutter from his Apple Watch (important for taking ninety-degree close-ups of fingerprints or tire tracks where the slightest vibration could blur the details).

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Simply browsing through the tablet he got us for crime scene work and nagged us for a few months to use before he finally gave up, I find:

The flashlight app. Of course. (I was at a crime scene yesterday where the two young men were trying to plug my USB into the video system, cleverly hidden in the ceiling panels. It’s dark up there, of course, and they were stymied as they had never downloaded a flashlight to their relatively new phones. I pulled my mini-Mag out of my pocket and suggested they use an actual flashlight. Sometimes us old chicks rule.)

Pill Identifier, with which you can enter the color and shape of a medication and it will help you narrow down to the name of the drug, then link to information on purpose, dosage, side effects and drug interactions.

Photo Measures, which allows you to take a photo of a room and then annotate it with measurements. This way my boss, the detectives, the prosecutors and the jury no longer have to suffer through trying to decipher my hastily scribbled sketches of uneven walls and amorphous blobs representing the pit couch. I can take a photo of the room and write the dimensions right over the picture, then add the feet and inches from the south wall to the bloody knife on the floor. The only catch is you still have to take the measurements yourself.

And for that, we have RoomScanPro. Simply start it up, give each room a name like ‘dining’, hold the phone against each wall, in order but at any particular spot on the wall until you’ve gone around the whole room. The app will create a floor plan including measurements. Do a complete walk-through and it will give you the whole house. Be warned, however, that these apps may only be accurate to half a foot, so that you could wind up with an attorney grilling you how the murder weapon could have been five and a half inches from the victim’s body instead of six.

For traffic incidents, Vehicle Identification System can give you pictures of nearly every make and model available in the last decade to aid witnesses in describing the getaway car. And Cargo Decoder can translate the four-digit DOT code on a truck’s placard to tell you what kind of materials they’re hauling.

There are a number of panoramic photo apps, so that you can quickly scan a 360° shot of the crime scene as is before EMTs, firemen, reporters, angry mobs or bigwig looky-lous breach your perimeter.

So the next time you see a team processing a crime scene it might not only be the nerdy young guy using the newfangled gadgets to do the job. It might be the grizzled old detective using a smartphone and a rubber-tipped stylus.

And reading glasses.

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Lisa Black has spent over 20 years in forensic science, first at the coroner’s office in Cleveland Ohio and now as a certified latent print examiner and CSI at a Florida police dept. Her books have been translated into 6 languages, one reached the NYT Bestseller’s List and one has been optioned for film and a possible TV series.

 
 
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