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Category Archives: General Forensics

Q and A: How Would the Time of Death Be Determined in a Corpse Found in Snow?

Q: In my story, the body of a young woman is found by cross-country skiers in high-mountain country. (Average temps in December: 20 degrees/low to 40 degrees/high;  elevation about 9000 ft.) If the person had been dressed in heavy clothes, and the body had been there about 24 hours, would it be completely frozen? Partially? Would there be any way to determine when death had occurred?

MT, Albuquerque, NM

Jack-Frozen

A: The corpse would be at least partially and could be completely frozen–perhaps with some of the deeper internal organs only partially frozen. It depends on the clothing, exposure, moisture, wind, etc. Also the old rule that whatever happens, happens comes into play here. So the freezing could be either complete or partial.

Under these conditions, rigor and lividity would be delayed to an unpredictable degree so these would be very crude indicators and not very useful in determining the time of death (TOD). Body temperature might be more useful—emphasis on might—but this would not be very accurate either. If the core body temp had reached the ambient temperature, this determination is of no use, since once the corpse reaches the ambient temperature it will remain stable at that temperature, making body temperature useless. For example, if the corpse reached the ambient temp after 18 hours then 24 hours would look like 36 or 48 as far as body temp is concerned.

But if the corpse hasn’t reached ambient temperature, core body temp can be used to estimate the TOD. Not very accurately but at least in the ballpark. Under “normal” circumstances, a body loses heat at about 1.5 degrees per hour, but this depends on many variables. Your scenario is definitely not “normal,” so temp would be lost more rapidly. Could be 2 or 3 or 4 degrees per hour if there is wind or cold rain for example. Let’s say the ME found the core temp was 40 with an ambient temp of 30. This means the body is still cooling since it has not yet reached ambient temperature. Let’s also say that in his experience he believes (educated guess at best) the body would lose about 3 degrees per hour under the circumstances he sees at the scene. If so, subtracting the measured corpse temperature (40 degrees) from the normal body temperature (98) and dividing by the rate of loss (3 degrees/hour) would yield the estimated TOD.

The math: 98-40 = 58; 58/3 = 19 hours.

Based on these calculations, your ME might conclude that the death occurred approximately 19 hours earlier, give or take a couple of hours.

Of course the major flaw here is that the actual rate of temperature loss might vary from his estimate so, despite the math, his assessment remains a best guess. He would likely suggest a broad range—maybe saying the TOD was between 16 and 24 hours earlier. That’s really the best he could do.

So your corpse could be partially or completely frozen and the time of death could be difficult to determine. Except for one more trick: stomach contents.

Let’s say the corpse is frozen so that temp, rigor, and lividity are of no help yet it was known that the victim had eaten a certain food at a certain time prior to his disappearance. It takes the stomach 2-3 or so hours to empty after a meal so if the ME found the undigested meal in the victim’s stomach and knew the time of this final meal from witnesses, he could then more accurately place the time of death as within 2-3 hours after that meal. Let’s say he had lunch around noon, went skiing, and was then found dead 24 hours later. If the ME found that last meal still in his stomach he might suggest that the TOD was between 1 and 4 p.m. the day before. This might be your best bet for narrowing down the TOD.

 
 

Crime and Science Radio: Inside the Los Angeles Regional Crime Lab: An Interview with Dean Gialamas

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This Saturday, February 1, 2014 at 10 a.m. PST join Jan Burke and DP Lyle as they welcome Dean Gialamas, Director of the Los Angles County Sheriff’s Department’s Crime Lab, to the show to discuss this unique lab, what it’s like be be a crime lab director, the new federal forensic science commission, and more!

Dean Gialamas is the former director of the Orange County Crime Lab, the current director of the LASD crime lab, and was recently appointed to the first-ever National Commission on Forensic Science.  He is a past president of the American Society of Crime Lab Directors, and the president-elect of the California Association of Crime Lab Directors.

The Los Angeles County Sheriff’s Department of Scientific Services is an ASCLD/LAB-International/ISO 17025 accredited laboratory that operates from 10 facilities and employs over 300 personnel.  It serves a population of six million residents and over 100 local, state, and federal agencies.

LISTEN

LINKS:

LASD’s Scientific Services

FBI Laboratory Services

The Crime Lab Project

How Stuff Works: How Forensic Lab Techniques Work

Forensic Science Timeline

Experts Named to National Commission on Forensic Science

Announcement of Formation of the National Commission on Forensic Science

LASD Scientific Services Bureau

LAPD Scientific Investigation Division

American Academy of Forensic Sciences

American Society of Crime Lab Directors

American Society of Crime Lab Directors – Laboratory Accreditation Board

International Association for Identification

California Association of Crime Lab Directors

Hertzberg-Davis Forensic Science Center

California Association of Criminalists

Dean Gialamas at NIJ 2010 on Backlogs as a False Metric

Forensic Science Education Programs Accreditation Commission

 

The Writers Forensics Blog: 100 Top Websites to Bookmark

The crew over at FornesicScienceDegrees.org have listed The Writers Forensics Blog as one of their Top 100 Websites to Bookmark, which they describe as a “list of great sites to present practical, real-world information on the subject.” Many great sources here.

Thanks. I’m flattered.

 

 

Sisters in Crime, Orange County, FORENSICS FEST 2014

Sisters in Crime, Orange County PRESENTS….

FORENSICS FEST 2014

Sunday, January 26 at 2 p.m.

Special guests: JAN BURKE and D.P. LYLE

Jan Burke is the award-winning author of the Irene Kelly mysteries, the Edgar winner for Best Novel (Bones), and founder of The Crime Lab Project.

D.P. Lyle is the author of best-selling books on forensics, as well as Stress Fracture, Book One in the Dub Walker series.

Together they’ve launched the twice-monthly internet radio show called “Crime and Science Radio” on Suspense Radio/Blog Talk Radio with John Raab. (Join them every other Saturday at 10 a.m., or catch their archived shows at http://www.suspensemagazine.com/CrimeandScienceRadio.html )

OPEN TO THE PUBLIC   

Come hear Jan and Doug talk crime & science and meet & mingle with crime writers & readers! 

And mark your calendars: FORENSICS FEST PART II will be held Sunday, February 23  

For additional details and location info go to http://www.ocsistersincrime.org

 

 
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Posted by on January 21, 2014 in General Forensics, Writing

 

Bloodstain Camera Finds Blood Quickly and Efficiently

Detecting blood at a crime scene is often essential for determining if a crime did indeed occur and how the act unfolded—crime scene reconstruction. At the scene, a meticulous search for blood can be tedious, time-consuming, and eat up many man-hours.

 

Techs search for bloodstains

Techs search for bloodstains

 

Shed blood is not always obvious. The stains are not always patent (visible) but rather latent (invisible). The standard in such situations has been to employ Luminol, which can find even very small latent bloodstains. But Luminol takes time and requires darkness—not always obtainable, particularly in outdoor, daytime crime scenes.

 

Luminol helps expose latent bloody shoeprints

Luminol helps expose latent bloody shoeprints

 

A new technology developed by Dr. Meez Islam and colleagues at Teeside University promises to not only be able to detect latent blood spatters quickly but also age the blood very accurately. With month-old stains the device, which uses hyperspectral imaging, can narrow its deposition down to a day and with fresh blood down to an hour. This should greatly help with Time of Death determination—-or at least the time when the blood was shed.

 

Fresh blood spatter

Fresh blood spatter

 

Blood exits the body bright red but with time and oxidation becomes rusty brown and does so along a predictable timeline. Accurate determination of the bloodstain’s color with hyperspectral imaging reveals its approximate age.

Very cool. And potentially very useful.

 

Crime and Science Radio: Jan Burke Interviews Cat Warren, Saturday at 10 a.m. PST

Listen in at 10 a.m. PST this Saturday or catch it later in the archives.

What the Dog Knows: The Science and Wonder of Working Dogs: An Interview with Cat Warren

Cadaver dog handler Cat Warren is the author of What the Dog Knows: The Science and Wonder of Working Dogs, a terrific book on dogs who work in the military, in police departments, and by searching for both contemporary and historical missing remains.  She talks with Jan Burke about how cadaver dogs and their handlers are trained, the environments and conditions they work in, and what we do and don’t yet know about how dogs find the missing dead.

http://www.dplylemd.com/DPLyleMD/CrIME_%26_SCIENCE_RADIO.html

http://www.blogtalkradio.com/suspensemagazine

LINKS:

Cat Warren: catwarren.com

What do we know about dogs noses?: http://www.science20.com/what_dog_knows/science_what_dog_knows-122271

Cadaver Dog (Andy Rebmann and Marcia Koenig’s site): http://cadaverdog.com

National Search Dog Alliance: http://www.n-sda.org

The National Missing and Unidentified Persons System (NamUS): http://namus.gov

FBI Statistics for Missing and Unidentified Persons in the US for 2012: http://www.fbi.gov/about-us/cjis/ncic/ncic-missing-person-and-unidentified-person-statistics-for-2012

RECOMMENDED READING:

What the Dog Knows by Cat Warren

The Cadaver Dog Handbook, by Andrew Rebmann, Edward David, Marcella Sorg

Analysis of Lost Person Behavior by William Syrotuck and Jean Anne Syrotuck

Canine Ergonomics: The Science of Working Dogs by William S. Helton

 

 

Ten Most Common Forensic Mistakes in Fiction

Ten Most Common Forensic Mistakes in Fiction: A fun Big Thrill interview with Jan Burke and I:

http://www.thebigthrill.org/2013/10/special-to-the-big-thrill-10-most-common-mistakes-in-fiction-regarding-forensics-by-d-p-lyle-jan-burke/

 

FORENSICS FOR DUMMIES: A Great Read

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“I have to admit it was a great read. I thoroughly enjoyed it.”

I didn’t say this—though I agree. But then I’m a bit biased.

But I’m thrilled that Tom Nelson, Director of the Forensic Services at the Scottish Police Service Authority (SPSA) enjoyed it.

 

 
8 Comments

Posted by on October 15, 2013 in General Forensics, Writing

 

Crime and Science Radio: The Science of Sherlock Holmes

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Tomorrow, Saturday, 9-21-13, at 10 a.m. Crime and Science Radio presents:

The Science of Sherlock Holmes: Jan Burke and Leslie Klinger

Leslie Klinger is a Holmes expert of the first order. His THE NEW ANNOTATED SHERLOCK HOLMES is one of the most highly regarded studies of Holmes and his creator, Sir Arthur Conan Doyle.  What influenced Holmes’s scientific and investigative methods?  And what influence has Holmes had on forensic science and criminal investigation?

DETAILS and LINKS

LISTEN

 

Breathprints? As Good as Fingerprints?

When we breathe, we take in air which is rich in oxygen (02) and expel air which is richer in carbon dioxide (CO2). The oxygen in the inhaled air is removed by the bloodstream and carried to the body so that the cells will have the oxygen they need to perform all their functions and indeed stay alive. A byproduct of cellular metabolism is CO2, which is picked up by the bloodstream and carried back to the lungs for exhalation. Good air in, bad air out. Simple and clean.

But the exhaled air contains more than just CO2. Hundreds of other molecules and compounds, also byproducts of our metabolic processes, are excreted by the lungs. These can be sampled and analyzed.

It seems that researchers at ETH Zürich and the University Hospital Zürich have begun analyzing exhaled air in the hopes of finding a “fingerprint” that could serve to individualize people. Much as true fingerprints and DNA do.

breathprinting_l

 

So far they have discovered that the chemicals exhaled by a given individual is highly specific and does not change dramatically over time. There are minor variations on a day-to-day basis but in general it seems that a person’s “breath print” is indeed unique. If so this could prove to be another useful method of identification.

Not to mention its medical possibilities. For many years doctors have used the odor of a patient’s breath to help make diagnoses. The odor associated with diabetic ketoacidosis, renal failure, and liver failure are each quite distinct. Though further testing is necessary to prove the diagnosis, it is often suspected from the odor surrounding the patient.

 
 
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