Tag Archive for: crime scene

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Extracting Nuclear DNA from Hair Shafts is a “Hairy” Situation

Law enforcement officers collect a variety of evidence at crime scenes, such as bullet fragments, weapons, narcotics, and fingerprints. In addition, police gather body fluids, skin cells, bones, and hairs, hoping that one or more of those substances will contain a suspect’s DNA.

But where, you might ask, is the DNA located? Well, it’s certainly not doing the backstroke in the pool of blood that leaked from a fallen victim of a gunshot. Instead, the DNA evidence sought by police—nuclear DNA—is contained within the nuclei of cells.

Cells, the Home of Nuclear DNA

All cells in our body are made up of a cell wall (cell membrane), cell fluid (cytoplasm) and a nucleus, with the exception of red blood cells and platelets. Since neither of latter two have a nucleus they do not contain DNA.

Nuclear DNA is made up of genetic material from our fathers and mothers. The nucleus of each cell contains a pair of chromosomes—, one from each parent.

Each cell typically contains 23 pairs of chromosomes, for a total of 46. Twenty-two of the pairs are called autosomes, and they look identical in both male and female humans. The 23rd pair are the sex chromosomes and they are distinctly different between males and females. Females have two copies of the X chromosome. Males have one X and one Y chromosome.

As evidence in criminal matters, DNA serves a dual purpose—identifying an individual as the source of the DNA found on an evidence item, or to exclude the individual as the contributor of the collected DNA evidence.

Now, we’ve briefly and generally discussed that DNA lives in cells, and those cells are where scientist go to retrieve the DNA needed for testing. And we know that DNA is readily found in body fluids, skin cells, bones, and for many years it was believed that testing hair for DNA was only possible if the bulb/root at the base of the hair shaft was intact. This was so because the keratinization process that creates the hair shaft during its growth often breaks down (lyses ) cell membranes.

DNA IS present, though, in hair shafts, but in small quantities. It’s quite short and fragmented, which is similar to DNA found in ancient remains. So yes, like testing DNA found remains of wooly mammoths and other beings and bits and bobs from long ago, it is possible to isolate nuclear DNA from rootless human hair samples.

In fact, to make this possible, a company called InnoGenomics uses a magnetic bead extraction system that’s specifically optimized for the process of capturing low-level, highly degraded DNA.

By combining InnoGenomics’ two DNA typing kits together—InnoXtract and InnoTyper 21 (IT21), the isolation and typing of nuclear DNA from rootless hair shafts is quite achievable. And, the process is compatible with Capillary Electrophoresis (CE) instruments, such as Promega’s Spectrum CE System.

So yes, crime writers, the heroes of your tales have a tool to add to their crimefighting toolboxes, because it is indeed possible to obtain nuclear DNA from hair shafts.

DNA Testing in General

The first step in the testing process is to extract DNA from the evidence sample. To do so, the scientist adds chemicals to the sample, a process that ruptures cells. When the cells open up DNA is released and is ready for examination.

Did you know it’s possible to see DNA with the naked eye? Well, you can, and at the bottom of this page you’ll learn how see the DNA that you, in your home kitchen, can extract DNA from split peas.

After DNA is extracted it’s then loaded into wells inside the genetic analyzer.

Scientist placing a well plate containing 96 individual wells into a genetic analyzer. Below right in photo is a closeup of a well plate.

Electric current separates the DNA, sending it from the wells through narrow straw-like tubes called capillaries. During its journey through the analyzer, DNA passes by a laser. The laser causes the DNA loci (a gene’s position on a chromosome) to fluoresce as they pass by, which allows a tiny camera to capture their images.

The image below shows DNA’s path from the wells through the capillaries past the laser.

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At the end of the testing, the equipment produces a graph/chart called an electropherogram, a chart/graph of peaks and valleys that precisely pinpoints where genes are located.

An allele is a term that describes a specific copy of a gene. Each allele occupies a specific region on the chromosome called a gene locus. A locus (loci, plural) is the location of a gene on a chromosome.

Peaks on the graph depict the amount of DNA strands at each location (loci). It is this unique pattern of peaks and valleys that scientists use to match or exclude suspects.

 

The image below, as ominous as it appears, is an electropheragram showing the DNA of a strawberry.

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Serial Killer Challenges DNA Results

*The following text regarding the appeal from serial killer Timothy W. Spencer, The Southside Strangler,” is from the US Court of Appeals for the Fourth Circuit. Spencer’s case was the first in the U.S. based on DNA evidence that resulted in the death penalty. I served as a witness to Spencer’s execution. Click here to read about my experience.

“Timothy W. Spencer, Petitioner-appellant, v. Edward W. Murray, Director, Respondent-appellee, 5 F.3d 758 (4th Cir. 1993)

US Court of Appeals for the Fourth Circuit – 5 F.3d 758 (4th Cir. 1993)Argued Oct. 28, 1992. Decided Sept. 16, 1993

J. Lloyd Snook, III, Snook & Haughey, Charlottesville, VA, argued (William T. Linka, Boatwright & Linka, Richmond, VA, on brief), for petitioner-appellant.

Donald Richard Curry, Sr. Asst. Atty. Gen., Richmond, VA (Mary Sue Terry, Atty. Gen. of Virginia, on brief), for respondent-appellee.

Before WIDENER, PHILLIPS, and WILLIAMS, Circuit Judges.

OPINION

WIDENER, Circuit Judge:

Timothy Wilson Spencer attacks a Virginia state court judgment sentencing him to death for the murder of Debbie Dudley Davis. We affirm.

The gruesome details of the murder of Debbie Davis can be found in the Supreme Court of Virginia’s opinion on direct review, Spencer v. Commonwealth, 238 Va. 295, 384 S.E.2d 785 (1989), cert. denied, 493 U.S. 1093, 110 S. Ct. 1171, 107 L. Ed. 2d 1073 (1990). For our purposes, a brief recitation will suffice. Miss Davis was murdered sometime between 9:00 p.m. on September 18, 1987 and 9:30 a.m. on September 19, 1987.

Miss Davis was murdered sometime between 9:00 p.m. on September 18, 1987 and 9:30 a.m. on September 19, 1987. The victim’s body was found on her bed by officers of the Richmond Bureau of Police. She had been strangled by the use of a sock and vacuum cleaner hose, which had been assembled into what the Virginia Court called a ligature and ratchet-type device. The medical examiner determined that the ligature had been twisted two or three times, and the cause of death was ligature strangulation. The pressure exerted was so great that, in addition to cutting into Miss Davis’s neck muscles, larynx, and voice box, it had caused blood congestion in her head and a hemorrhage in one of her eyes. In addition her nose and mouth were bruised. Miss Davis’s hands were bound by the use of shoestrings, which were attached to the ligature device. 384 S.E.2d at 789.

Semen stains were found on the victim’s bedclothes. The presence of spermatozoa also was found when rectal and vaginal swabs of the victim were taken. In addition, when the victim’s pubic hair was combed, two hairs were recovered that did not belong to the victim. 384 S.E.2d at 789. The two hairs later were determined through forensic analysis to be “consistent with” Spencer’s underarm hair. 384 S.E.2d at 789. Further forensic analysis was completed on the semen stains on the victim’s bedclothes. The analysis revealed that the stains had been deposited by a secretor whose blood characteristics matched a group comprised of approximately thirteen percent of the population. Spencer’s blood and saliva samples revealed that he is a member of that group. 384 S.E.2d at 789.

Next, a sample of Spencer’s blood and the semen collected from the bedclothes were subjected to DNA analysis. The results of the DNA analysis, performed by Lifecodes Corporation, a private laboratory, established that the DNA molecules extracted from Spencer’s blood matched the DNA molecules extracted from the semen stains. Spencer is a black male, and the evidence adduced at trial showed that the statistical likelihood of finding duplication of Spencer’s particular DNA pattern in the population of members of the black race who live in North America is one in 705,000,000 (seven hundred five million). In addition, the evidence also showed that the number of black males living in North America was approximately 10,000,000 (ten million). 384 S.E.2d at 790.”

How You Can Easily Extract DNA From Split Peas!

Easy “pea-sy” DNA extraction

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Academy Instructor Detective Sergeant Dilly Pickle: Homicide Crime Scenes

Good morning, cadets. My name is Detective Sergeant Dilly Pickle. I’m your instructor today and my topic is Introduction of Homicide Crime Scenes.

Before we begin I want you to totally scrub your minds clean of everything you’ve seen about crime scene investigation on television and film, and that you’ve read in many crime novels. Much of the stuff out there is a convoluted tangled mixture of information that’s bad, good, and downright fantasy, so it’s best we start fresh, with the basics.

Now, let’s see a show of hands. How many of you think you know where a homicide scene begins?

You there, in the back … Yes, you are 100% correct. A homicide crime scene begins at the point or place where the suspect’s thoughts of committing the murder transformed into action. And, the “crime scene “continues to any place where evidence of the crime could be found, such as the entire route taken by the suspect as he left the place where the crime occurred—through the back door, into and around a garden shed, across the neighbor’s lawn, down an alleyway, the sidewalk on Maple Avenue, the abandoned dirt lot the kids use for baseball games, and, well, you get the idea.

Any questions? No? Let’s continue.

The primary homicide crime scene, however, is always the location where a body is discovered. Sometimes victims are murdered in one location but their bodies are transported to other areas as a means to conceal the crime. In those instances the place where the body is found is the primary homicide crime scene. The site of the murder, when it becomes known, then becomes a secondary crime scene. All other locations where evidence could be/is discovered—footprints, a cigarette butt discarded by the killer in the backyard, the murder weapon in a dumpster three blocks away, are secondary crime scenes. Of course, many times the primary homicide crime scene and the location of the body are one and the same.

  • A crime scene is any location where potential evidence may be located.

  • Scene of the crime is the specific, physical location where a crime occurred.

There are nearly as many different ways to approach and investigate a crime scene as there are detectives in line at donut establishments. I suspect their orders—chocolate-covered, glazed, bear claw, etc.—are as diverse as their personalities and ways they approach the job. But, despite the menagerie of varying quirks and thought processes, there are things that should be done at all homicide crime scenes. For example …

Document the findings at the crime scene:

1. Document air temperature at the scene (ambient air).

2. Document body temperature—cold, warm, frozen, etc. This is “to the touch.” Cops do not insert thermometers into any portion of a human body.

  • Algor mortis is simply the cooling down of the body after death. It’s the quest to reach room temperature.One method of determining the time of death is to take the rectal temperature of the deceased. Next, subtract that number from 98.6 (average, normal human body temp), and then divide the remaining number by 1.5 (the average cooling rate of a body per hour under average conditions). The result is the approximate number of hours that passed after the victim kicked the bucket.

3. Document livor mortis (lividity)—was livor mortis present, and at what stage? Was it fixed? Was body position consistent with the stage of livor mortis? Did someone move the body?

  • Livor Mortis, or lividity, is the pooling of blood in the lowest portions of the body. Lividity is caused by gravity and begins immediately after death. The telltale signs of livor mortis, the purplish discoloration of the skin, begins the moment the heart stops pumping. This process continues for approximately 6-12 hours, depending upon surrounding conditions, until it becomes fixed, permanently staining the tissue in the lowest parts of the body. When large areas become engorged with lividity, the capillaries in those areas sometimes rupture causing what’s known as Tardieu spots. Tardieu spots present as round, brownish blacks spots.

4. Document rigor mortis—what stage of rigor? Was the rigor consistent with the crime scene? Did someone move the body?

  • Rigor Mortis, the contracting and stiffening of the muscles after death, takes a couple of hours to begin and completes in approximately 8-12 hours. The process starts in the smaller muscles of the head and face and moves downward to the larger muscles. When rigor is complete, the process reverses itself starting with the lower large muscles and ending with the smaller face and head muscles. The entire process can last for approximately 48 hours. The body will quickly decompose after rigor is complete.

5. Document degree of decomposition—skeletonization, putrefaction, mummification, etc.

I know many of you have plans to travel to the beach this weekend, so before you go you should study the article below. And, yes, you”ll be tested on the information. So, please click the image to begin reading.

Bacteria Beach: Postmortem Decomposition and the Talking Dead

6. Document animal activity—was the body in any way altered by animals?

7. Photograph the body exactly as it was found. And, the ground beneath the body should be photographed once the body has been removed.

8. Document victim’s physical characteristics—description of the body, including scars, marks, tattoos, clothing, jewelry, and obvious wounds).

9. Make note of the type of on-scene emergency medical care, or the lack of treatment.

10. Document presence of body fluids and where they’re found (mouth, nose, beneath the body, etc.). Also note if there’s no indication of body fluids.

11. Bag the victim’s hands (and bare feet) in clean, unused paper bags.

12. Collect, or arrange for the collection of trace and other evidence.

13. Determine the need for alternate light sources and other specialized equipment.

DSC0097014. Photograph the victim’s face for future identification purposes (remember, most present-day identifications are done via photograph or video).

15. Make note of the presence of insects. Photograph and collect samples of each.

16. Protect the body from further injury and/or contamination.

17. Supervise the placement of the body into a body bag, and install the proper seal/securing.

18. Ensure the proper removal and transportation of the body.

19. Who, What, Where, How, and When. Who discovered the body? Who was present when the body was discovered? Where was the body discovered? How was the victim killed? When was the body discovered? Who witnessed the murder? Etc. Document all, no matter how insignificant it sounds at the time.

20. Document EMS records/activity. Obtain a copy of the EMS call sheet/report, if possible.

21. Document witness statements—what they observed, the victim’s actions prior to death, killer’s description, etc.

22. Note medical examiner’s comments.

23. Obtain witness statements and contact information.

24. Document the names and contact information of everyone present at the scene (officers, EMS, medical examiner, witnesses, etc.).

25. Be certain that all evidence has been recovered before releasing the scene.

Well, that’s it for today’s class. You have twenty minutes to change into your PT attire and assemble on the lawn outside the dorms. We have a nice five-mile run lined up for your enjoyment, followed by an hour of stimulating exercise.

See you tomorrow.

 

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Crime Scene Investigation Taboos: The Dirty Dozen

Detective I. Will Gitterdone had a spotless attendance record, never missing a day for sickness in his entire thirty-three years with the department. In fact, in all of his years of wearing a badge and toting a sidearm he refused to soil that record even though on this particular day his fever hovered at 102, and coughing and sneezing fits forced him to spend the majority of the morning with his mouth and nose buried deep into a crumpled and quite yucky handkerchief. His arms and legs felt heavy and his muscles felt as if he’d been trampled by a hundred stampeding wild pigs.

In spite of the aches, fever, chills, and perspiring like a Savannah ditch digger working in August midday sunshine, Gitterdone was busy collecting suspected blood samples (brownish-red stains for the official record) at a particularly brutal homicide scene. He was also spewing misty spittle via alternating coughs and sneezes. His partner, Al Lergictowork, told him he looked worse than bad and asked if he needed a break. Gitterdone promptly turned his head away from Lergictowork to fired off a round of lung-clearing ah-choo’s directly into the large paper bag of already-collected evidence. “No,” he said. “I’ll be okay. Besides, I’m almost done here.”

So, did you notice anything particularly wrong with Gitterdone’s method of evidence collection? Was there anything he should have done differently?

Well, I think it’s safe to say that it might be a good idea to have both Gitterdone and Lergictowork study this list of Crime Scene Do Nots. It would also be wise to have your protagonist take a peek, just in case.

Crime Scene DO NOT’S

1. Do Not blow away excess fingerprint powder! Doing so adds your DNA to the surface.

2. Do Not use Styrofoam to package electronic devices (computer parts, etc.) because it can cause static charges. Instead, use foam padding or bubble-wrap.

3. Do Not alter or add anything to a crime scene sketch after leaving the scene. Memories are not quite as accurate as we may think.

4. Do NOT place bloodstained evidence in plastic bags. Plastic bags and containers can serve as incubators for bacteria, which can destroy, alter, or deteriorate DNA. Rule of thumb—paper bags/containers for wet evidence (blood, semen, saliva, etc.) and plastic for dry evidence.

5. DO NOT collect DNA evidence samples (saliva, blood, etc.) from a criminal suspect without a court order, the suspect’s consent, or under exigent (emergency) circumstances.

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6. Do NOT cough, sneeze, exhale, etc. over any evidence sample. This includes talking over a sample. With each word spoken comes your DNA that’s instantly transferred to the evidence.

7. Do NOT fold wet documents. Leave that to the professionals in the lab.

8. Do NOT use fingerprint tape or lifters to collect bits of trace evidence. The adhesion on print-lifting tape is typically insufficient for picking up tiny bits of evidence.

9. Do NOT use dirty digging tools when collecting soil samples. Always clean tools thoroughly after each use to avoid cross contamination.

10. Do NOT use fingerprint lifters in lieu of gunshot residue (GSR) collection materials. (see number 8 above)

11. Do NOT allow shooting suspects, victims, witnesses, etc. to wash their hands or rub them against other surfaces until after GSR tests/collection have been completed.

Finally, number twelve is one that writers should do, and that’s …

12. Attend the 2020 Writers’ Police Academy/MurderCon. We have an unbelievably cool and over-the-moon exciting lineup in store for you. This is an event you will not want to miss!!

Honestly, we’ve outdone ourselves this year. We’ve been sitting on a few exciting secrets about the 2020 event and it’s almost time for the big reveal. So stay tuned, because we’ll soon be releasing the details.

MurderCon is moving forward as planned. We have carefully detailed plans in place for proper social distancing, and we’re furnishing masks. Hand sanitizer will be readily available.

Sirchie, our host, is in the loop with state and local health officials since they’re in the business of making PPE equipment, including hand sanitizer and masks, for 1st responders. Between Sirchie officials and our in-house microbiologist, Denene, we’re closely monitoring the situation and making preparations. Your safety, as always, is our priority.

Sign up today to reserve your spot!

MurderCon 2020

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Bacteria Beach: Postmortem Decomposition and the Talking Dead

During their crime-solving duties homicide investigators hear and see a lot of details—gunfire, fleeing suspects, yelling and screaming, pleas for help, blood and viscera, and even the sounds of their own hearts as they frantically beat against the inside walls of their chests.

But once the dust settles around the crime scene, and all is quiet, it’s time for detectives to focus their attention on the murder victim and what they have to “say.” Believe me, they have a quite a story to tell.

Bacteria Beach

Before we take our walk on Bacteria Beach, let’s first join an enthusiastic group of writers for a very brief introduction of the topic du jour. Please click the play button.

Now, on with Decomposition!

Putrefaction is the destruction of the soft tissue caused by two things, bacteria and enzymes. As the bacteria and enzymes do their jobs the body immediately begins to discolor and transform into liquids and gases. The odd thing about the bacteria that destroys tissue at death is that much of it has been living in the respiratory and intestinal tracts all along.  Of course, if the deceased had contracted a bacterial infection prior to death, that bacteria, such as septicemia (blood poisoning), would aid in increasing the body’s decomposition.

Temperature plays an important part in decomposition. 70 degrees to 100 degrees F is the optimal range for bacteria and enzymes to do what they do best, while lower temperatures slow the process. Therefore, and obviously, a body will decompose faster during the sweltering days of summertime.

 

A blood-filled circulatory system acts as a super-highway for those organisms that destroy the body after death. Without blood the process of putrefaction is slowed.

  • A murder victim whose body bled out will decompose at a slower rate than someone who died of natural causes.
  • Bodies adorned in thick, heavy clothing (the material retains heat) decompose more rapidly than the norm. Electric blankets also speed up decomposition.

Bodies decompose faster during the sweltering days of summertime

A body that’s buried in warm soil may decompose faster than one that’s buried during the dead of winter. The type of soil that surrounds the body also has an effect on the rate of decomposition. For example, the soil in North Carolina is normally a reddish type of clay. The density of that clay can greatly retard the decomposition process because it reduces the circulation of air that’s found in a less dense, more sandy-type of earth.

Adult bodies buried in a well drained soil will become skeletonized in approximately 10 years. A child’s body in about five years.

People who were overweight at the time of their deaths decompose faster than skinny people. People who suffered from excessive fluid build-up decompose faster than those who were dehydrated. And people with massive infections and congestive heart failure will also decompose at a more rapid rate than those without those conditions.

The rule of thumb for the decomposition of a body is that, at the same temperature, 8 weeks in well-drained soil equals two weeks in the water, or one week exposed to the air.

Now, hold on to your breakfast …

The first sign of decomposition under average conditions is a greenish discoloration of the skin at the abdomen. This is apparent at 36-72 hours.

Next – Small vessels in the skin become visible (marbling).

Followed by, glistening skin, skin slippage, purplish skin, blisters, distended abdomen (after one week – caused by gases), blood-stained fluid oozing from body openings (nose, mouth, etc.), swelling of tissue and the presence of foul gaseous odor, greenish-purple face, swollen eyelids and pouting lips, swollen face, protruding tongue, hair pulls out easily, fingernails come off easily, skin from hands pulls off (gloving), body swells and appears greatly obese.

Internally, the body is decomposing and breaking down. The heart has become flabby and soft. The liver has honeycombed, and the kidneys are like wet sponges. The brain is nearly liquid, and the lungs may be a bit brittle.

Okay, I’m done for now. But before you go, here’s a reminder, from me to you …

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Tater Jenkins Done Killed Uncle Billy Buck Robinson: The Crime Scene

“Tater” Jenkins done killed Uncle Billy Buck Robinson. Quick, call the law afor’in’ that son-of-a-biscuit-eatin’ coward gets clean away!”

And so it goes. Aunt Ruthie Mae runs next door to use Lula Belle’s rotary phone to call the police, a department of four men and women of varies sizes, from rail thin to chair-crushing fat—who, after one last bite, drop their newspapers and circular, creme-filled morning breakfast food and trot out to their cars to make the treacherous drive up Banjo Mountain. But not before stopping by the drive-through at Percy’s Pork Skin Palace to grab a sack lunch for the long trip. Along the way, they pass by Billy’s goats, Carl’s cows, several mangy dogs, and a cross-eyed bear who was in the midst of overturning Miss Ethel Turner’s outhouse.

The determined officers motored across Falling Car Creek and the Killzemall River by using makeshift bridges, a handcrafted series of large logs that stretched across the waters. Then, after stopping for lunch and seven breaks behind assorted species of trees (NOT an easy task for the two female officers), the patrol officers finally reached their destination, a grouping of six obviously homemade clapboard-sided, rusty-tin-roofed houses nestled along the hillside, seven miles from the nearest sunshine. Curb appeal was limited to crooked eaves, sagging beams, and lopsided stone chimneys that blew and belched smoke the color of tar paper. Several red-headed children ran to and fro, playing some sort of game that involved a single crooked stick. Their dirt-smeared faces and arms were spattered with summer freckles.

A three-legged mutt slowly lifted its head when the police cars pulled to a stop, dragging clouds of white dust in their wakes. The dog, uninterested in the action, lowered its head and resumed its nap.

Mr. Onion Parson, a man with a single tooth that sat slightly askew in a mouth as dark as a cavern, called out, “Over here, Five-Oh!”

“One Tooth” shooed a few chickens from their new perches atop the forehead of one very blue and very cold Uncle Billy Buck Robinson. “He’s right here, and he’s deader’n a doornail,” said Onion. “He done chopped Billy Buck in the haid with my best ax.”

Later, the lead officer would include in her official report, a description of that remarkable tooth as “shaped exactly like the state of Delaware.” She noted that a bystander saw Tater flee the scene on the back of a mule named Homer. However, the officer omitted all references to the chickens, an unfortunate decision that would come back to haunt her when a savvy defense attorney pointed out to the jury that the presence of chicken prints on the forehead of the deceased raised the possibility of “murder by rooster” and not by an ax-wielding Tater.

“After all,” the attorney said to the judge, “a very aggressive rooster named Killer was known to violently attack the hands that fed him. Heads, too.” Another point omitted from the officer’s report. The jury agreed with the defense attorney and “Tater” Jenkins walked away from the trial a free man. The rooster, however, was sentenced to serve as Sunday dinner. The hens, obviously brainwashed by their leader, were not charged, citing Stockholm Syndrome as their defense.

Preserving a Crime Scene

So, what really happens once patrol officers arrive on scene? Well, for starters, much of the above could be sort of true. I recall meeting several people during my career who could’ve been members of these fine families.  However, here’s how it really happens …

Screen Shot 2017-02-09 at 10.31.23 AMFirst on the Crime Scene

Uniformed officers are normally the first police officers on the scene. It’s up to these front-line cops to take charge, calm the chaos, and make things safe for citizens in the area, EMS and firefighters, and for the arriving investigators, medical examiner, etc.

Sometimes, crime scenes are large and complicated; therefore, it may be necessary to set up a command post—a central location for coordinating police activities.

Many police departments use some sort of mobile command centers, such as converted motor homes and travel trailers. Some patrol supervisors drive vehicles designed to quickly transform into a fully functional command post.

A command post could be, however, anything and anywhere—a local store, store parking lot, an officer’s patrol car, and so on.

The Two Types of Perimeters

  • the first is an overall periphery for the purpose of containing suspects within a specific area.
  •  an area to preserve the crime scene and the evidence within.

Crime scenes may be as small as a single room, or they can be as large as several city blocks, or more. There are no set boundaries. Investigators on the scene make this determination, as needed.

It’s best to establish a large boundary at first to ensure that all evidence is protected from outside interference/contamination/disturbance. You can always reduce the size of the permitter, but enlarging it after the fact is mostly a waste of time because there’s a risk of evidence being disturbed by bystanders, news media, EMS, firefighters, other officers, etc.

Do not rush into a crime scene without first taking everything in. Take a moment to assess the area. Are there any dangers, including hidden ones, such as gas leaks, poisonous chemicals, A KILLER WITH A GUN?

Absolutely do not allow anyone inside the scene unless they’re a vital part of the investigation team. This includes members of the police department, including command staff. Of course, if a chief insists, well, make certain to document her entry and exit times.

Do not allow anyone to leave the area until you’ve interviewed them. Treat every single person as a possible witness. Sometimes people don’t realize they’ve seen an important detail until they’ve been questioned by police.

Crime Scene Investigation Facts:

Carey A. Body just murdered his longtime girlfriend, Ida Kissedanyman, and fled on foot through an alley, over a fence, and into the rear parking lot of Beulah Bell’s Hog Jowl Emporium. Body, sweating heavily and breathing like a huffing locomotive traveling a 72% steep uphill grade, ditched the murder weapon inside a fat rusted dumpster that was stuffed to the brim with discarded hocks, pinto beans, and hunks of Crisco-drentched fried cornbread.

Therefore, even though the dumpster was four blocks away from the actual scene of the crime, the dumpster is now considered a crime scene. Why? Because evidence of a crime is located there. And, yes, detectives and/or CSI’s must paw through the garbage, by hand, searching for evidence.

More crime scene investigation facts …

  • Patrol officers often assist investigators/detectives with the recovery and collection of evidence.
  • Not all crime scene investigators are sworn police officers. Many police departments employ specially trained civilian crime scene investigators/technicians. Non-sworn crime scene investigators do not:

(As seen on TV)

  • arrest criminals
  • interrogate or question suspects
  • carry weapons
  • participate in, or conduct autopsies
  • engage in foot or vehicle pursuits
  • handcuff criminal suspects (What goes on during their free time is of no concern to us. Unless, of course, you’re writing a scene involving hot, steamy … you know).

All police officers are trained to properly collect and preserve evidence. After all, sometimes detectives are unavailable. Therefore, in those instances, uniformed officers assume the duty of investigating the crime.

detective and patrol officer bagging a gun at a crime scene

The police are in charge of crime scenes. Coroners and medical examiners are in charge of the bodies of murder victims.

NOTE: Not all medical examiners and coroners show up at crime scenes. In those instances, EMS or a local funeral home typically transport the bodies to the morgue where the M.E. will have a look as soon as possible. Detectives, in these instances, are in charge of the body and sometimes travel in the ambulance to the morgue to preserve chain of evidence/custody.

Releasing information to the media—hold your cards close to your chest until you have an idea of what information can be released to the public. Remember, what you say will be on the evening news! I know this one all too well…unfortunately.

Hamilton One 121

*As always, rules, policies, and procedures vary from area to area and agency to agency. If 100% accuracy is your goal then you make a quick phone call to the public information officer (POI) at your local police department. This is often the officer you see providing official updates on your evening news.

 

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