The tickle of curiosity. The gasp of discovery. Fingers running across the keyboard.

The World of Iniquus - Action Adventure Romance

Showing posts with label Science in Society. Show all posts
Showing posts with label Science in Society. Show all posts

Monday, March 10, 2014

Forensic Serology: Body Fluid Information for Writers


______________________________________


Soldiers of the United States Army Criminal In...
 (Photo credit: Wikipedia
At the scene of a violent crime, investigators will look for serology samples.
(CSI blog link)

Serology is simply the study of bodily fluids.

These fluids include:
* Blood
* Semen
* Saliva
* Sweat
* Tears
* Vomit
* Vaginal secretions

These fluids can be found either on the skin or transferred to another surface.


While serology tests can EXCLUDE a subject who is thought to be a person of interest, it can not find them culpable.

Serology tests are class studies and cannot tie a body fluid to a specific and unique source.
Only DNA testing can link a specific individual to a crime. (DNA blog link)



Presumptive tests - likelihood of something being what you think it is in the field.

* Sometimes a false positive - but you never want a false negative because then a detective could walk away
   from evidence and make false conclusions about the scene

Is there blood present but not visible to the naked eye?
* Fluorescein - precursor to Luminol goes back to 1900s
   `Is not thwarted by chlorine bleach
Blood Stained Floorboard Treated with Luminol
Blood Stained Floorboard Treated with Luminol (Photo credit: Jack Spades)
   ` Uses UV light to glow
   `Still used in the field today
   `Thicker than Luminol so good for
     vertical surfaces
* Luminol/BlueStar
   `Does not work if chlorine bleach
    was used to clean up the blood
   `Complicates further testing by
    diluting the blood
   `Needs darkness



When you write a scene that includes either of these tests, please remember that the blood is not visible to the naked eye because it was cleaned up. When the blood was cleaned, it was smeared around. The Luminol or Fluorecein will show up in smear streaks NOT blood spatter. NOT hand prints.

Video Quick Study (2:49) Shows luminescence of BlueStar

Is that blood? Testing for a visible stain:
At FBI doing serology tests
* Leucomalachite Green
   Video Quick Study (4:28)
* Kastle-Meyer test - phenolthaline and hydrogen
   peroxide that detects the hemoglobin in blood
   cells.
   `produces a dark pink.
   `blood can come from any animal
   Video Quick Study (1:01)

Video Quick Study (7:41) CSI teacher shows how the three presumptive blood tests are conducted.


Once the presumptive tests show that a substance is blood then the collection is sent to the lab where they undergo confirmatory tests:

1. Is it human blood?

   * The serology labs have stocks of antigens that are found in animals but not humans.
   * Samples of common animals such as: dog, cat, rabbit, deer, chicken etc. antigens  are maintained for
      testing.
   * If the test shows an antigen reacting with an antibody then that determines the species type.

2. Once it is determined that the blood is human then blood test typing is done.
   * Blood Type
Diagram of ABO blood groups and the IgM antibo...
Diagram of ABO blood groups and the IgM antibodies present in each.  (Photo credit: Wikipedia)
    `ABO system
    `Rh Protein (not used in forensic science)
    `Genetically inherited
    `Can be determined not just from
     blood but also from other body secretions.
    ` Blood type is class evidence. It is NOT
      individuating evidence. So it can only be
      used to show that someone COULD NOT
      have done the crime but cannot be used to
      prove that some did - that would require
      DNA




Video Not Quite So Quick Study (14:00) Goes over this thoroughly if it is an important point in you plot and you need a firm grasp on the importance of blood typing.




Semen

Sperm (album)
Sperm (album) (Photo credit: Wikipedia)
* Can be found in a dead woman's body for up
   to two weeks
* In a living sexual assault victim sperm can only
   be found for about five hours after the crime
   occurs
* After 72 hours in a live victim there may be no
   remaining evidence of sperm or semen
* Acid phosphatase is a presumptive field test.
   Acid Phosphate is made in the seminal
   vesicles in males but also in:
   `non-human animals
   `plants and fungi
   `found in vaginal fluids.
* Microscopic search for sperm cells in a
    sample is a confirmatory test
 * Microscopic sperm search is NOT useful if
    the man has had a vasectomy
* PSA (Prostate-specific Antigen) is considered
   confirmatory

Video Quick Study (1:01) Acid Phosphatase Test


Video Quick Study (3:15) Storage and container information for serology samples
Video Quick Study (2:31) Serologist at trial giving testimony - note the packaging of the items

Using various wave length light sources to find bodily fluids at a crime scene
All body fluids fluoresce except for blood which absorbs light
Body fluids must be dry to fluoresce except for urine (which will sometime fluoresce when wet)
Video Quick Study (2:00)


Thank you so much for stopping by. And thank you for your support. When you buy my books, you make it possible for me to continue to bring you helpful articles and keep ThrillWriting free and accessible to all.


Enhanced by Zemanta

Friday, December 6, 2013

Skeletons in Her closet: The Forensics of Skeletons for Writers



___________________________________________________________________________________

I curled up like a cat on Miriam’s living room couch with a cup of hibiscus tea steeping on the table beside me. Miriam was on the phone with the police, jotting notes about a case they wanted her to work for them. Someone’s Great Dane came home this morning with a human skull in his mouth. The detective needed a jump-start – some information to get going with while the skull waited its turn on the forensics lab shelf. ~ WEAKEST LYNX










Writers, if your crime scene includes skeletal remains or even remains that have advanced to a soupy mess, the person who is called in to take control of the bones is a FORENSIC ANTHROPOLOGIST.
***NOTE: The forensic anthropologist is applying their post graduate studies in biology and anatomy as well as their understanding of trauma to research the bones. They do not solve the crime. They do not interview suspects or witnesses (LINK to Interrogation for Writers). They simply: study, document, report, testify (where necessary).


Forensic anthropologists can help identify ske...
Forensic anthropologists can help identify skeletonized human remains, such as these found lying in scrub in Western Australia, circa 1900–1910. (Photo credit: Wikipedia)



Forensic Anthropology - Dem Bones!
Video Quick Study (3:13) Tanya Peckmann talks about her job.

Servicemembers search for POW/MIAs on Wake Isl...
Servicemembers search for POW/MIAs on Wake Island Greg Berg uses a sifter to look for bone and artifacts at a dig site Jan. 12 on Wake Island. Mr. Berg, a forensic anthropologist, was sent to do a site survey after Wake Island officials notified the Joint POW/MIA Accounting Command of bones located on the island. JPAC officials are charged with achieving the fullest possible accounting of all Americans missing as a result of past conflicts. (U.S. Air Force photo/Tech. Sgt. Shane A. Cuomo) (Photo credit: Wikipedia)
The job of Forensic Anthropologists is to make some determinations concerning the skeleton that was discovered or exhumed. They are called in by officials to remove the remains.
* Remains are placed in a body bag for transport to a
   forensic laboratory.
* The remains are reconfigured to a supine position, and
   photographed.
* Any remaining soft tissue is cut away from the skeleton
* The bones are abraded with steel wool to remove dirt,
   bugs, and soft tissues.
* The bones are then soaked in a chemical solution to
    further clean and prepare them for examination.

This Video Quick Study (12:04) is a non-narrated look at a forensic anthropologist team at work





The Forensic Anthropologists attempt to make the first sets of identifying data:
* Approximate age
FAFG - coded corpse
FAFG - coded corpse (Photo credit: xeni)
* Sex
* Size/height
* Ancestry


AGE:


* Teeth and bone growth help to identify the proper age.
* Precise age determination is easier in children than in adults because of the statistical probability of various
   developments taking place in teeth and bone fusion/growth plates.
* Age results for adult remains are given in broad ranges.
* 206 is the average number of bones of an adult.
* An adult  skull has approximately 22 bones.
Parts of a long bone
Parts of a long bone (Photo credit: Wikipedia)
* A newborn skull has approximately 44 bones.
* In assessing age in children, the long bones of the body
   show dramatic changes with age.
*ossification of the growth plates follow general
  standards:
  - First growth plates close at the elbow
  - next ankles, knees, hips, then shoulders.
  -  The last growth plate to close up is the central tip of
     the clavicle around 23-28. (health and nutrition
     effects this age span)

Video Quick Study (1:48) - bone changes from infancy to adult

   * Teeth form from crown to root.
   * At birth primary teeth are already present in the jaw.
   * At 6 mos most infants have visible teeth.

Video Quick Study (3:17) Dr. Snow identifies Gacy's
                                        victims by age.


English: diagram of a human female skeleton, b...
. (Photo credit: Wikipedia)

SEX:

* Prior to puberty, the skeletal remains cannot
   be identified as male or female without DNA.
* A pelvis in a female is wider from front to back.
* Joints tend to be larger on males.

THE SKULL - this information is statistically correct. Measurements are made and compared at different points on the skull to determine a statistical probability rather than a 100% certainty.
* Male occipital protuberance is larger to attach larger
   neck muscles.
* Male brow ridges are larger
* Women tend to have higher smoother foreheads.
* Male jaws tend to be at a 90 degree angle with
   squared corners.
* Women's jaws tend to be smoother with
   pointier chins

Video Quick Study (2:35)





the adult skull is normally made up of 22 bone...
the adult skull is normally made up of 22 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibres permitting a little flexibility (Photo credit: Wikipedia)

SIZE AND HEIGHT


* Is best identified from a full skeleton.
* Statistics have been developed to allow a range based on skull size.

the adult skull is normally made up of 22 bone...
the adult skull is normally made up of 22 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibres permitting a little flexibility (Photo credit: Wikipedia)

ANCESTRY

* Without DNA ancestry is difficult.
   LINK to DNA article
* DNA is best harvested from the teeth, though it is
   possible to extract from bone.
* Skull structure yields the biggest clues about
   race/ancestry based on math formulas.
* Few people today come from a racially pure
   ancestral line, making identification more difficult.
* In order to apply the statistics to ancestral
   identification, a fairly intact skull is required.


Skeletons under excavation at Walkington Wold
Skeletons under excavation at Walkington Wold (Photo credit: Wikipedia)

Beyond excavation (LINK to Crime Scene Info for Writers), and the preliminaries of age, sex, size and ancestry, a forensic anthropologist can offer investigators other identifying information:
* History of bone breakage
* History of surgical interventions such as ACL replacements and other injuries where screws and implants
   were used.
* Nutrition over the life span
* Toxicity over time such as arsenic or mercury.
* Exposure to heavy metals like lead

* They can also help determine the number of skeletons in a mass destruction such as a large fire or plane
   accident.

They can inform and testify about stab wounds and what type of weapon might have been used through trauma analysis.
* Was the break:
   - antemortim trauma - before death like healed fracture or screws from surgical repair.
   - post mortem trauma - what happened to skeleton after the death - like an animal
   - perimortem trauma - bone damage at or around the time of death, such as  a broken jaw or cracked
     skull.

To gather this information they use CAT scans, and other medical diagnostic machinery.
Video Quick Study (3:51) Discusses high-tech tools.





Thank you so much for stopping by. And thank you for your support. When you buy my books, you make it possible for me to continue to bring you helpful articles and keep ThrillWriting free and accessible to all.

Enhanced by Zemanta

Monday, October 7, 2013

Crime Scene 101 for Writers: Decisions. Decisions.

___________________________________________

CRIME SCENE DO NOT CROSS / @CSI?cafe
 (Photo credit: Wikipedia)
I just finished reading Mike Roche's book, THE BLUE MONSTER. It was a wonderful window into urban police investigation. One of the things that I appreciated about the book was understanding how individual competencies in processing a crime scene can make all of the difference in bringing a perpetrator to justice.

To this end, I thought that this week on the blog we could look at some decisions that writers can make and different points at which things can go well, or a writer could twist the plot.


WRITERS' DECISION MAKING


STEP ONE -  Is it safe to go on the scene?

1. Do you have a hazardous environment called a HOT ZONE?
   A  Hot zones can be created by
       * natural disaster - such as Tsunamis in Japan, floods, fires, and storms
       * mass disasters - such as terrorism
       * crimes - like the anthrax filled envelopes through U.S. Postal Service
       * accidents
   B. Hot zones might include
      * nerve gas
      * radioactive materials
      * nuclear threat
      * chemicals creating toxic and/or combustible threats
      * bio-hazards such as pathogens, venom, and parasites along
         with other disease causing organisms

2. Is the bad guy still on the scene?

3. Did they plant booby-traps or bombs Link to bombs article


STEP TWO - Will the first response team get there in time?
* To save the victim(s)?
* To save the house?
* And in their attempts to preserve life and/or preserve property
   will they damage the evidence to
   make it harder to solve the crime?


STEP THREE - How effective will your First Responders be when they contain and secure the scene?


Soldiers of the United States Army Criminal In...
. (Photo credit: Wikipedia)

* Only someone with a good reason to be at the crime
   scene is allowed in the area - this precludes the media,
   the family, and PI's. In Janet Evanovich's books
   Stephanie Plum really can't just walk in and look
   around because she happens to be doing Morelli.
* Others who might contaminate your scene and
    twist your plot might include looters and bystanders
* An officer has to stand at the entrance of the scene
   and log in everyone who enters and exits the police
   tape including the precise times when they entered and
   exited.
* Others who enter a crime scene can introduce
   Finger prints Link to finger print article
   Foot prints Link to footwear article
   Hair
   DNA Link to DNA 101 article
   Tire prints

Now this might be a good place to talk about Locard's Exchange Principle:

Whenever someone moves throughout an environment there will be an exchange of materials.
* A person will pick up materials such as animal hair, dirt, and fibers and take them away with them.
* A person will leave trace evidence showing that they were there - fingerprints, hair strands, DNA from spit
   or blood.
* The longer that two people are in contact and the more intense their exchange the more trace evidence will
    be left in place.

Imposing Lokard's Theories there will be a transference. This is why any superfluous people need to be kept from the scene.
* When extra information is introduced it slows the process and creates extra work for the investigators
   because they have to sort through all of the data.

Another reason to keep others at a distance:
* Public access has to be restricted so that someone with a cellphone etc. won't be releasing information
   to the public.
* The police typically only release information that is critical to identifying the perpetrator.
* They keep the rest quiet so they can monitor the story.
   For example, in interrogation Link to Interrogation article a suspect lets slip a piece of information that
   only the perpetrator or someone who had seen the scene would know. This is a big piece of evidence
* This also helps prevent copy cat cases because the full MO has not been revealed. Maybe that's just what
   your plot needs.






A Crime Scene at the National Museum of Crime ...
A Crime Scene at the National Museum of Crime & Punishment (Photo credit: Wikipedia)


STEP FOUR : How competent are your investigators in gathering and processing evidence?


VIDEO QUICK STUDY (11:41) good overview poor sound quality.
VIDEO QUICK STUDY (25:52) A little long but this is the process from the military (US Army)

* Proper warrants are obtained (a property owner can give consent for searches)
* A search strategy is developed by the officer in charge
   This prevents the crime techs from damaging or overlooking evidence
   This usually happens before the investigators enter a scene. Everything must be considered even the spatial
   relationships of objects, blood spatter patterns etc.
* There are four main types of searches -
English: Footwear impressions left at a crime ...
English: Footwear impressions left at a crime scene. (Photo credit: Wikipedia)
   line search 
   circular (or spiral) search 
   serpentine search 
   funnel search
* Evidence is identified -
   1 Trace Evidence - (also called Micro-evidence)
      tiny pieces like sand, saliva, latent prints.
   2 Real Evidence  (also called Tangible Evidence
     and Macro Evidence)-  physical objects
      that inform a case or played a part in the incident.
 * Everything in the area is potential evidence
 * Assumptions are made prior to scientific analysis -
    Is it blood? Is it cocaine?
 * Field Tests are conducted (like blood swabs)
 * Pattern Evidence - Helps to understand the scene.
     This is protected with photography (digital and
      video) VIDEO QUICK STUDY (5:39)
   * Maps are created
   * Measurements of all pertinent pieces of evidence
      are documented.
   * All objects are measured from one set
      point called a datum. 
   *This is sometimes done with
     portable computerized mapping systems called
     Total Station Serving Systems
   
VIDEO QUICK STUDY  (9:51) excellent lecture on evidence collection. Shows process and equipment in use.
*Macro search
   1. hunt and peck
   2. flashlight
   3. alternate light Link to alternative light article go to
                         second half
   4. taping
* Micro Search
    1. vacuum
    2. fingerprinting
    3. using chemical solutions (such as BlueStar or Luminol)
    4. swabs


STEP FIVE - Did your responders process everything correctly so that it is useful in making a case and also permissible in court?


* Documentation
   `Crime Scene inventory list is created identifying each marker
   ` Chain of custody list
* Preservation
* Transportation of evidence

STEP SIX - The investigators hand the evidence over to the scientists and a whole new set of complications can twist your plot. Have fun!

See how this article influenced my plot lines in my novella MINE and my novel CHAOS IS COME AGAIN.




Thank you so much for stopping by. And thank you for your support. When you buy my books, you make it possible for me to continue to bring you helpful articles and keep ThrillWriting free and accessible to all.

Tuesday, April 2, 2013

Fingerprinting For Writers by Patti Phillips

A big thank you to Patti for sharing her wonderful experience!



Sirchie makes hundreds of products for the law enforcement community and offers classes in how to use those products at their Youngsville, North Carolina Education and Training site. Several crime writers were allowed an unprecedented opportunity to attend a five-day, hands-on training session, so that we could learn more about the latest and best gadgets being used to catch the crooks.




Included was incredibly valuable information about fingerprinting. Robert Skiff (Training Manager/Technical Training Specialist at Sirchie) put us right to work, using the powders and brushes needed to process a crime scene and used by actual techs in the lab.

                              Fingerprint powders, brushes and magnifier




There is no such thing as a perfect crime, but the jails are filled with crooks that swear they have been framed. Common excuses: “I was at my girlfriend’s house at the time of the crime,” “Somebody planted that shoe print,” etc. It’s up to the investigators and examiners to prove the case against the suspects, using proper evidence collection techniques and tools, because trace evidence is ALWAYS left behind by even the most careful criminal.

Fingerprints found at the scene are still the favored piece of evidence tying the suspect to the crime. These days, using a combination of ingenuity and newly developed chemicals and powders, a crime scene investigator can lift (and/or photograph) prints from many previously challenging surfaces.


About a month before the session started, we got a letter in the mail telling us NOT to wear good clothes to class. Hmmm… My thought was that we were going to be doing some messy evidence collections outdoors or in the mud, etc. Nope. Black fingerprint powder gets all over everything when newbies are handling it for the first time. We must have used 50 wet wipes each during the morning alone.




                                          After dusting prints with black fingerprint powder,








they were lifted from various smooth surfaces using (in forefront) a gel lifter, a hinge lifter and (in background) tape.





We had to be careful not to contaminate the powders and jars or smear the samples themselves before looking at the prints under the magnifier. By the end of the day, most of us had black eyes and streaks on our hands and faces. It looks much easier on TV.

Our prints were photographed and then viewed under an Optical Comparator. This machine can be hooked up to a laptop, and the image sent off to AFIS for identification purposes. No crooks in our crowd, so we omitted that step.






At the end of the first day we left happy, tired, and still wiping powder off our hands and faces. A tip from an investigator taking the class with us: add a cup of vinegar to the wash load to get those powder stains out. 

Day One take aways?

*Not all powders can be used on all surfaces.
*A print can dissipate over time and there are too many variables (temperature, humidity, condition of the surface, etc.) to predict how long that might take.
*A really crisp print can be photographed right at the scene, using some great digital cameras now available.
*Forensic science is not a certainty, even though TV shows may give that impression.
*There is no nationwide standard for number of points of ID for a fingerprint. The fact that the acceptable number of matching points (between the actual print and the print in the AFIS database) can range from 5 to 20 depending on where the perp lives, blew us away.


Day Two: Coffee ready. Snacks ready. Notebooks, cameras, smartphones, and pencils ready. Checking for leftover fingerprint powder on the magnifier. Ready.

Robert Skiff’s assistant for the class, Chrissy Hunter, passed out stainless steel rectangles and we pressed our fingers onto the plates, twice. First time - plain ole print, second time - ‘enhanced’ by first rubbing our fingers on our necks and foreheads to increase the amount of oils in the print. The ridge detail in the prints was so clear in the ‘enhanced’
version that there was no need to process them with powder. We lifted them with a gel lift.

If we were working a real scene, that might never happen, but it could. The usual occurrence is that partial prints are left at the scene and that’s what makes the search for the perps sooooo much tougher than what the TV dramas indicate. There is no instant ‘a-ha’ moment that comes 45 minutes after the crime has been committed.

The prints are generally sent off to be compared with the millions in the AFIS database, and here’s where TV parts with reality again. AFIS comes back with a list of 10-20 possible matches and someone then makes a comparison by hand of the most likely hits.

After practicing the basics, it was time to move on to fingerprint discovery on documents. Documents? Yup. There are scheming relatives who forge wills, less than loving spouses who murder for the insurance, bogus suicide notes, and the list goes on. How to prove the nefarious intent? Fingerprints. But…as we discovered the first day, fingerprint powder is messy and almost impossible to clean up. An important document could be destroyed in the search for evidence of foul play. Enter chemicals and alternate light sources (ALS).



There is a protocol for testing with chemicals. If the prints don’t show up with one chemical, then it is possible to try several others, but this can only be done in a certain order:

Iodine
DFO
Ninhydrin
Silver Nitrate
MBD

If used in this order, the sample won’t be compromised, even though treated several times over several days.

We experimented with several chemicals with excellent results, but for the ‘wow’ factor, I’m showing the ones that look great on camera. ;-)




DFO reacts to amino acids in the prints. We created our samples placing our own enhanced prints on plain white paper. We hung the papers in the fume hood, saturated them with DFO, then put them in the oven to bake for several minutes.









This DFO sprayed, baked sample doesn’t look like much, so it was time to use an ALS to really ‘pop’ the print and make it photo ready.





Alternate Light Sources vary depending on the scene lighting and/or need to highlight the evidence. A few used in the field are: the ‘poor man’s ultimate light source’ (a mag light), black lights, UVC lights, lasers, LED lights, Ruvis lights (cost about $20K), and pure white lights. Each has a specific quality that the investigators can tap when needed.






After we sprayed our samples with DFO and baked them in the oven, we darkened the room, and put on orange plastic glasses. Then we side-lit the sample with a 455nm light. The photo was taken at that point.






Same sample, side-lit at a slightly different angle. Photo taken through an orange filter.



Ninhydrin, the third chemical group in the list to be used if nothing has shown up yet, comes in several forms: acetone, zylene and Noveck. Ninhydrin reacts to another set of amino acids and likes warm, moist air. If a sample is being saved overnight for processing, you can place it in a ziplock bag, blow into it, then seal it and still maintain its integrity.

Before working with any chemical, it’s a good idea to make copies of the document. Why are there different kinds of Ninhydrin? Zylene will run some inks. Acetone will run all inks, all the time. Ooops! There goes the document if you grab the wrong chemical, so copies are definitely necessary. Noveck is the clear winner when working with inks. It gets fast results and dries quickly. Additionally, it can be sprayed on an outer envelope to reveal what’s inside. Without damaging either piece of paper. Very cool.


You could see the plots developing in our writerly heads as the Noveck dried and the words inside the folder faded from view.



*Photos taken by Patti Phillips at the Sirchie Education & Training site in Youngsville, NC.
Patti Phillips writes Detective Kerrian’s blog at www.kerriansnotebook.com and the book review site www.nightstandbookreviews.com

Enhanced by Zemanta