Where to Find DNA Evidence

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Can’t seem to find the right clues for your current work-in-progress? Well, here’s a handy guide to help with locating DNA evidence.

  1. Undergarments (boxers and/or briefs, etc.)
  2. Sweat-stained clothing
  3. Semen stains on clothing, bedding, skin and other areas of the body
  4. Pages of books and magazines
  5. Drinking cups
  6. Glass (window panes, mirrors, etc.)
  7. Ear wax
  8. Fingernail clippings/beneath attached nails.
  9. Used towels
  10. Urine
  11. Used stamps
  12. (Inner) cheek swabs
  13. Hair (with root is best)
  14. Dried blood
  15. Whole blood
  16. Chewed gum and similar candies/food items
  17. Dental floss and toothbrushes
  18. Cigarette butts
  19. Used tissue
  20. Dried skin, including dandruff and psoriasis
  21. Used razors
  22. Furniture (couch cushions, mattresses, and more)
  23. Carpeting
  24. Computer keys and mouse
  25. Used/worn stocking masks, gloves, mittens, caps, socks, pants, shirts, etc.

By the way, the odds of two people having the same 13 point DNA profile is approximately 1 in 1 billion. And…
 

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Evidence Collection: Paper Or Plastic?

There’s more to evidence collection than merely bagging and tagging bloody clothing and spent bullet casings. Crime scene techs are highly trained, skilled members of police agencies and forensic laboratories who more often than not provide the keys to solving cases.

In the “good old days,” many officers collected their own evidence. They plodded into and poked around crime scenes, determining what items they thought might be of some value, and then tossed those things into some sort of containers—grocery bags, envelopes, boxes, and even the cellophane wrappings from cigarette packs. In those days there wasn’t a lot of consideration for sterility, and DNA hadn’t yet made it’s way on the scene.

When investigators finally discovered plastic sandwich and ziplock bags you’d have thought they’d won the lottery, because packaging evidence had suddenly become a breeze. The problem with those new-fangled containers, though, was that detectives were placing everything in them, not knowing they could be destroying or damaging evidence instead of preserving it. And that brings us to the question of Paper or Plastic?

There’s a simple rule of thumb for deciding which type of evidence packaging—wet evidence goes in paper containers (wet evidence can degrade if placed inside plastic containers) and dry evidence goes in plastic. Items that could be cross-contaminated must be packaged separately. There’s a rule of thumb for other types of evidence, too, and here’s a handy list for the proper packaging of those items.

Hair – Double packaging in paper is best. However, if the hair is completely dry, plastic will work in a pinch. Hairs recovered from different locations must be packaged separately and labeled accordingly. Tape all packaging seams.

Fibers – Dry, and tape-lifted, fibers may be placed inside plastic containers.

Rope, twine, and other cordage – Paper or plastic.

Paint chips – Place inside folded paper. Then place the paperfold inside an envelope.

Tools – Paper or cardboard.

Tape – Wear non-powdered gloves when handling tape. Submit samples inside plastic. If the tape is stuck to an item the item must be submitted with the tape still attached. Do not remove the tape!

Glass – Wrap in paper. Smaller pieces may be placed inside appropriate size cartons.

Arson and other fire evidence – Airtight metal containers. Unused paint cans work best.

Dried stains – Wrap stained item in paper or place inside cardboard box. Large items – moisten swab with distilled water, swab the stain, and package in paper or cardboard after drying.

Blood – Allow to air dry and then package in paper.

Evidence drying lockers

DNA – NEVER use plastic!
And when I mentioned that wet evidence is packaged in paper containers I did NOT mean to pour liquids into paper bags. Instead, items that contain wet evidence (bloody and/or semen-stained clothing, etc.) should be placed into paper containers.
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6 Methods of Tracking Bad Guys…and Grandma’s Settee

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Working as a deputy sheriff in a rural county often presents its own set of special and sometimes unusual challenges, especially during the days before the existence of GPS, cellphones, and radio repeaters. In other words, it was pretty darned easy to get lost while traveling a convoluted maze of paved (sort of), dirt, and/or gravel roads. Roads with names like Burnt Tree Road, Red Clay Way, or Turkey Trot Lane.

Many of those winding back-roads led to five or six house communities where it was the norm for us to stop and ask for directions, and some of those kind folks, thinking it would be best for us to speak directly to the person we sought, allowed us use of their telephones. Besides, they didn’t want to be known as the one who sent the law after their friends. After all, liquor stills and pot grows were pretty popular in those days.

So, after a couple of rings and a loud “Hell-Oh,” this is what we sometimes heard as a response to our requests for directions to someone’s home.

“Go past Robert Junior’s old horse barn—the old one, mind you, not the fancy new one—and hang a sharp right at the big oak tree. Then go on down until you see a red mailbox. That ain’t ours, but you’re close. We’re just past where John Henry Daniels used to have a store. Now, it burned down 37-years ago next week, but they’s a big rock there with some yaller paint on it. Yaller was John Henry’s favorite color so his wife, Etta Jean—she’s Romey and Winonna Jenkins’ oldest daughter—painted the rock so’s everybody’d remember him and the store. If’n you knowed him you’d know John Henry sold the best pickles and peaches this side of Atlanta. That he did.

Anyways, if you get to where the road splits into a “Y” you’ve done gone too far, so turn around in Mable Johnson’s driveway—it’s the one with the deer head a-nailed to the cedar post next to road (her daddy used to be a taxxy-dermis)—and head back the way you come. Our house is the blue one a’settin’ off the road about two-hundred yards—the one with the goats and chickens running ’round the place. You can’t miss it, ’cause one of them goats ain’t got but three legs. Oh, whatever you do, blow the horn three times when you drive up so we’ll know it’s you, not those pesky Joe Ho’vers Witnessers. We all lay down on the floor behind Granny’s old settee when they come a knockin’.”

True story…sort of.

Anyway, to this day, driving on dirt and gravel roads takes me back to the day when unpaved streets and roads were sometimes my best friend when trying to follow a criminal’s trail. Dirt, mud, grass, and even sandy soil can be quite telling…if you take the time to look. Here are a few things investigators look for when following a trail.

1. Both cars and trucks sometimes lose traction when heading uphill, and when they do the tread patterns aren’t clear. When going downhill, tread patterns usually remain unbroken (clear) because the rubber maintains full traction with the surface. Therefore, investigators can easily determine the vehicle’s direction of travel.

2. When viewing tire tracks in the grass it’s important to note whether or not the tracks are shiny/glossy, or not. Glossy tracks mean the vehicle was heading away from the spot where you’re standing. Off color, or slightly dull tracks indicate the vehicle was heading toward your position.

3. When traveling on slightly muddy surfaces (about the consistency of slush), the vehicle’s tires force (squirt) mud forward at a +/- 45 degree angle.

4. Mud puddles, small creeks, etc. are perfect for telling which direction a car or truck is moving. Vehicles always push and pull water in the direction of travel. The liquid also washes away tracks on the exit side of the water. So, if you see a puddle with clear tracks leading up to the water’s edge, and no tracks and a wet surface on the opposite side of the puddle, then you know the vehicle was traveling toward the wet road surface. You may also see wet spots on the dirt road from where water dripped off the car frame, after it passed through the puddle.

5. Wet soil often sticks in the grooves of a tire tread pattern. As the vehicle moves along, the soil begins to dry and falls off, and it always does so in the direction of travel. Investigators can follow the trail much like following a trail of breadcrumbs.

6. When viewing tire tracks always position yourself where the track is directly between you and the sun. This enables the best view of the track’s details.

The same is true for examining footwear impressions.

6. Be sure to photograph the track for later comparison to a tire or shoe.

Finally, as you travel, be sure to examine the sides of the roadway and down paths and trails for the suspect vehicle. It would be pretty darn embarrassing to discover you’d passed by the crooks who’d parked in Mable Johnson’s driveway to count the stolen loot.

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Murder Really Bugs Me: The Insects

When investigators find maggots on a body that are in their early larvae stages, say…oh…when they’re 5mm in length, well, officers will then have a pretty good idea that the victim has been there for only a day and a half, or so.

Even the mere presence of certain insects is quite telling.

Now, please do enjoy your Thanksgiving dinner!

 

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Explosions: Collecting The Evidence

Every good thriller has at least one big explosion, right? You know, the “big boom” that always takes place right after the heart-stopping car chase, just before the hero rescues the kidnap victim who’s about to die at the hand of the cleverly-written villain. Yes, that explosion.

What we don’t see in our favorite thriller, though, is the collecting of evidence at explosion scenes. So let’s take a moment to examine that aspect of the scenario. What should be happening in the background while the hero is saving the world?

1. Bombings/explosions are not for the Sam Spade’s of the police department. Nope, these crimes should be worked by specially-trained investigators, as well as a team of experts that includes (but is not limited to) bomb disposal technicians, photographer, forensics/CSI team, medical examiner (if needed), structural engineer(s), building safety official, power company technician, additional officers to help search, etc.

2.  Bombing scenes are apt to change at any moment (parts of a building may suddenly collapse, etc.), therefore, the  investigator must be constantly aware of the surroundings, and he/she must thoroughly evaluate and re-evaluate before allowing evidence collection to begin.

3. As always, the scene should remain secure. A command post should be established, as well as a secure and safe location for staging collected evidence.

4. Locate and dispose of all remaining active explosives, utilizing canines, bomb robots, explosive detection chemicals, etc.

5. To avoid contamination, the team should wear protective clothing as they collect evidence and control samples. The special clothing also protects the investigator’s skin from toxic material.

6. Evidence from various locations at the scene should be stored separately (do not mix).

7. Collect ALL evidence, including suspected bomb parts, batteries, wires, samples from crater, and the usual hair, fibers, blood, etc. During autopsy the medical examiner will also collect fragments removed from victims,

8. Document the scene—blast effect (are street signs leaning away from the blast scene? if so, indicate direction. trees down? cars overturned?), debris (type, amount of, and distance from the blast site), victim(s) location before and after the blast occurred.

9. Medical examiner should conduct full-body x-rays, searching for components of the bomb and other foreign material relevant to the crime.

10. And, without fail, the investigator should always…walk softly.

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When The Bullet Hits The Bone

Writers often ask what kind of entrance and exit wounds are produced by police ammunition. And you know me, I’d rather show than tell. So please follow me to an underground indoor shooting range located at a sheriff’s office somewhere in the U.S.

And, since we’re conducting research, we may as well make that experience as fun as we possibly can. So let’s start out with a Thompson sub-machine gun (think Bonnie and Clyde and the early FBI). Before going any further, though, you may want to first scroll down and click on the video at the bottom of the page, letting it play as you read. Oh, and be sure to turn up the volume. The song could very well enhance your journey through this brief article.

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This extremely heavy weapon fires .45 cal. rounds, unloading its magazine with unbelievable quickness.

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The rounds (bullets) in the photograph above are hollow-point bullets similar to the rounds fired from the Thompson sub-machine gun. This is what they look like before they’re fired. They’re about the diameter of the Sharpie pens authors use to sign books. That’s pretty close to the size of most entrance wounds – the size of the bullet.

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The picture above is of one of the .45 caliber rounds after it was fired from the Thompson machine gun. The round passed through the self-healing wall tiles in the firing range, striking the concrete and steel wall on the the other side. Hitting the solid surface head-on caused the bullet to expand and fracture, which creates the exit wound we see in shooting victims (the hollow point fills with the material it strikes causing expansion of the bullet).

To give you a better idea of just how much the hollow point expands when hitting some solid, the round copper center you see in the photo above is the size of the original .45 cal. bullet.

Many times, bullet slivers break off inside the body causing further internal damage. The size of an exit wound depends on what the bullet hits inside the body. If the bullet only hits soft tissue the wound will be less traumatic. If it hits bone, expect much more damage. Easy rule of thumb – the larger the caliber (bullet size), the bigger the hole.

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close contact chest wound caused by 9mm round – post-autopsy (note the stitching of the “Y” incision

Bullets that hit something other than their intended target, such as a brick wall or a metal lamp post, can break apart sending pieces of flying copper and lead fragments called shrapnel into crowds of innocent bystanders. Those flying fragments are just as lethal as as any intact, full-sized bullet.

FYI – Bullets don’t always stop someone. I’ve seen shooting victims get up and run after they’ve been shot several times. And for goodness sake, people don’t fly twenty feet backward after they’ve been struck by a bullet. They just fall down, moan a lot, and bleed. That’s if they don’t get back up and start shooting again.

 

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