They have many names and assorted packaging styles. Some are used in one area of the country while others are used elsewhere. They’re often called by their official given names, but many refer to them simply as “rape kits.”

No matter what they’re called, Physical Evidence Recovery Kit (PERK), Sexual Offense Evidence Collection kit ( SOEC), Sexual Assault Victim Evidence kit (SAVE), they’re all designed for one purpose. For the collection of biological evidence in cases of sexual assault and rape.

Typically, when a victim of sexual assault comes to the hospital, an exam is conducted by a specially trained forensic nurse. The victim will also be seen by a physician. First, the medical experts will make sure there are no life-threatening injuries. Then they’ll ask questions about the assault, health history, medications currently taking, etc.

Next comes the actual physical exam conducted by the forensic nurse, including the collection of the victim’s clothing (in the area where I worked the hospital provided new, clean sweat pants and t-shirt if the victim didn’t bring extra clothing), DNA swabs, hair samples, including a combing of pubic hair to collect possible samples left by the attacker. Blood samples are taken, especially if the victim believes she/he may have drugged as part of the assault. A number of hair samples from the victim are also collected.

Victims may refuse any part of the exam, and they may take a break at any time. They may also elect to NOT report the assault to police.

The collected evidence is placed in various pre-packaged containers provided in the evidence collection kits (rape kits). Kits contain items such as swabs, white sheets (placed beneath the victim during the exam), bottles and plastic bags.

In my jurisdiction, the hospital kept a supply of PERK kits in their inventory. The PERK kit is the evidence collection kit authorized by the Commonwealth of Virginia. This is not the case in all states. Please check with authorities in the area where your story is set if you desire to use an actual name as opposed to “rape kit.”

SAVE evidence collection kit – Arrowhead Forensics

SAVE evidence collection kit – Sirchie

FYI – officers DO NOT use the term “rape kit” when around victims of sexual assault and rape. To do so is extremely insensitive, which is why officers in Virginia refer to the kits as PERK kits.

In the meantime, police are busy collecting evidence elsewhere—bedding (sheets, pillowcases), suspect clothing, and the suspect, if identified and located. Sometimes police take an entire mattress as evidence.

Once the forensic nurse completes the exam the evidence recovery kit is sealed and delivered to the lab for processing, which can take many weeks to complete depending upon backlog.

Many writers have asked about the length of time DNA evidence remains viable in sexual assault cases, and where it can be found. Here’s a handy rule of thumb guide. Remember, various circumstances could change or alter these time-frames.

1. Vaginal DNA samples – up to one week.

2. DNA from skin contact – up to two days. If, for some reason, the victim has not bathed it is possible to obtain a suspect’s DNA sample up to a week later.

3. Oral swabbing with positive results – up to two days.

4. Anal – three days.

5. DNA from suspect’s penis – twelve hours after the assault.

6. DNA from fingers in vagina – up to twelve hours.

*By the way, semen can be detected on clothing despite washing. Remember, though, it is possible that DNA can be transferred from one item to another during washing. This is called tertiary transfer.

Those of you who attended Dr. Dan Krane’s presentation at the Writers’ Police Academy may recall when he described how this is possible. In fact, as a world-renowned DNA expert, he’s testified about tertiary DNA transfer in high-profile court cases.

Therefore, writers, it is possible for a DNA sample to show up on the clothing of completely innocent person, such as the unsuspecting roommate who shares a load of laundry with his buddy the psycho- serial rapist. How’s that for a plot twist!

 *Thanks to Wally and crew over at crimescenewriter for the topic idea!

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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.

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

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.

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.

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.

In prehistoric times, when crime-solving technology was basic, almost non-existent, evidence-matching was a daunting task. Remember those days? You know, way back in the early 2000’s… Well, bullet-to-firearm matches were especially tough in those oh-so-distant times. Investigators first recovered spent ammunition, the bullet or bullet fragments and/or the part of the round that once contained the powder (cartridge). Then they set out on the mission of trying to match those bullet parts to the weapon that fired them.

Markings on the surface of a fired bullet – Larry Reynolds photo

Two fired cartridges – Larry Reynolds photo

To do so, they examined the recovered evidence for specific markings left behind by the firearm—lands and grooves left by the pattern inside the gun barrel, and firing pin and ejector marks left on the cartridge.

Then, investigators set out on the mind-numbing task of manually searching scores of image databases and other evidence comparison collections, hoping to locate a match to their piece of evidence. And it sometimes took forever and a day to find a match, if then.

Well, in 2003 a new star in the evidence-matching world was born…IBIS. The Integrated Ballistics Identification System. IBIS is totally automated, much like the AFIS and CODIS systems (fingerprint and DNA systems). Once IBIS hit the scene, investigators were able to enter an image into the system, starting a search of images from all databases AND from all current, on-going, and past crime scenes. And all this is done automatically, without having to paw through page after page of pictures.

But, it’s still not like you see on TV. There’s no moment where an image of a bullet pops up on a computer screen next to a picture of a suspect, complete with the thug’s address, phone number, and shoe size.

Investigators still must compare the items by hand and eye to determine that the two images, the image of the evidence and the database image, are indeed a match.

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Imagine how difficult it is to solve a murder when all you have as evidence is a single fingerprint. And, that print is not in any database, anywhere.  Sure, there were eight men who were seen near the scene of the crime on the night it occurred, but you have nothing solid pointing you in their direction.

Man, if only that print could talk.

I guess, for starters, the print could tell the investigator what the suspect had been holding in his hand, recently. For example, a cigarette, or a bottle of beer. Or even a bag of cocaine. But would it help to know if the fingerprint belonged to a smoker? Well, during your surveillance of the suspects you’ve seen six of the eight puffing away at various times. So that’s not a lot of help. How about if the print belonged to a person who drank alcohol? During the course of your investigation you’ve learned that only four of the suspects consumed alcohol. And you verified that information with family and friends. What about a drug user? Would it help to know if the print belonged to a drug user? After all, one of your informants says the guy with the big ears and red hair smokes crack regularly. So you try to dig up similar information about the other seven. Nothing. They’re all clean. No drugs. Red-On-The-Head is the only one who uses drugs.

So, if you knew for sure that the print belonged to a drug user and one of your only seven suspects is a confirmed crack smoker…What does that tell you?

The fingerprint, if it could talk, would probably say,

“Look, I’ve told you the guy smokes crack. What else do you want? You know what they say…If he walks like a duck and quacks like a duck…he’s probably the killer.”

But can a single fingerprint provide that sort of information? Sure it can, and here’s how.

Our bodies deposit metabolites—tiny traces of what we’ve consumed—into the sweat released from the pores located in our fingerprint ridges. Scientists use gold nanoparticles to detect the metabolites in fingerprint sweat to learn what, exactly, that individual has taken into his body, such as cotinine, a metabolite of nicotine. And the beauty of detecting cotinine is that a person would have had to ingest it, not merely touch a tobacco product, for it to show up in test results.

The process is simple. Dab the print with a solution containing gold nanoparticles with attached antibodies that bind to the metabolite. Scientists then apply a second antibody, one that binds to the cotinine antibodies. This solution also contains a fluorescent dye. If the person is a smoker, the dye will then glow along the ridge patterns when exposed to an alternate light source.

The test is also capable of testing for alcohol and drug use, which could help narrow a field of suspects. If the test detected cotinine and the guy you’re looking at for the murder is a non-smoker, then you need to at least start looking for an accomplice.

“I always wanted to be a detective when I grew up, and I’ve finally made it. Now, if I only had somewhere to pin a badge…”

*     *     *

Want to learn more about fingerprints and the equipment used to detect them? How about bloodstains? Well, you’re in luck. A team of experts from Sirchie Fingerprint Laboratory will be on hand at the Writers’ Police Academy and they’ll be presenting a couple of mind-blowing demonstrations. Bring your questions and your cameras!

http://www.writerspoliceacademy.com/

Important!

* Have you reserved your hotel room for the Writers’ Police Academy? If not, please do so today. The block of rooms we reserved at the Embassy Suites is nearly full and there may not be any additional rooms available once those are gone. You won’t want to miss out on any of the fun! Ask for the Writers’ Police Academy discounted rate.

* Also, spaces for the Writers’ Police Academy are filling fast, therefore, we may be at capacity soon. So register today for this one of a kind event. Remember, Sisters in Crime will pay over half of your registration fee! This offer is open to everyone. See the WPA website for details.