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Category Archives: Crime Scene

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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DNA Solves the 80-Year-Old Death of Belgium’s King Albert I

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Belgium’s King Albert I was found dead on February 17, 1934. The experienced rock climber was found at the base of a large formation with a gash to his head. Speculation that he was murdered ran rampant. During World War I, he had resisted Germany and attempted to block German troops from entering his country. They eventually did, but he fought them every step of the way. Was Germany somehow complicit in his untimely death?

Many felt that he had been killed elsewhere and his body dumped where it was found. The evidence suggested otherwise. His glasses were found nearly 40 feet above him – – he was very far-sighted – – and his climbing rope was still attached to his body. But, the most important evidence that suggested a fall rather than a murder was blood on the leaves near the King. If this blood was indeed Albert’s, then he must have shed it at that location, meaning he was at least briefly alive when he reached the ground at the base of the rock formation. If he had been killed elsewhere and dumped, there would have been no blood around the body. Dead folks don’t bleed. The leaves were apparently collected and preserved.

Flash forward to 2014. The blood of the leaves was tested. Not only was it human blood and but also it was matched against two relatives of the King. These results suggested that the blood was indeed the King’s blood and it had likely been shed from a head injury he received from his fall. This 80-year-old “murder” case seems to be a tragic accident.

 

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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How Old Is That Fingerprint?

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Fingerprints are useful forensic science tools. They’ve been so for over 100 years. Mainly, it’s the pattern of the ridges on the fingertips that supply the useful information. We know that everyone has different fingerprints and we know that they do not change throughout the person’s life. This means that they are highly reliable sources for identification and for discrimination between two individuals. Law enforcement has employed this for years.

But several newer techniques and analyses allow investigators to go even deeper. The skin cells, that are part of a fingerprint, can often yield DNA. Chemicals in the print residue can sometimes reveal if the person has used or handled such substances as cocaine. Other analyses are underway that might make fingerprints even more useful.

One question that frequently plagues crime scene investigators is exactly when a print was laid down. This determination can make a huge difference. Let’s say that a print is discovered at a homicide scene and the primary suspect says that he had been at that location but that that had taken place a week earlier. Not on the day of the killing. Is he telling the truth? Or simply trying to throw the police off and make an excuse for the evidence they collected against him? It would be nice to know if the print was 24 hours old or seven days old.

Research is currently underway by Shin Muramoto and his colleagues and they reported their initial findings in a recent article in Analytical Chemistry. They discovered that a chemical found in fingerprints known as palmitic acid migrates away from the ridges at a predictable and consistent rate. By looking at this migration pattern they are able to determine whether the print is fresh or up to four days old. They are looking to extend this envelope to a longer period of time. But you can see, that even this level of discrimination could help—or not—- the suspect in the above scenario.

 

The World’s First Homicide?

No one knows for sure when the world’s first homicide took place – – other than Cain and Abel, that is. But it just might have happened 43,000 years ago in northern Spain. A skull retrieved from the Sima de los Huesos (Pit of Bones) in the Atapuerca Mountains showed two circular puncture wounds in the forehead of the skull. The skull had been found shattered into 52 fragments but miraculously was nearly complete. Once it had been reassembled the two wounds were easily identified. Researchers believe they were made by the same instrument and that they were not consistent with a simple fall into the cave shaft.

When you examine the skull it definitely looks as though some pointed instrument, most likely a stone tool or weapon, had delivered the blows. Of course, the assailant could claim self-defense, but this looks like a homicide.

 

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

 
 
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