Blog Archives

Future Forensics: The Problem with Biometric Guns

If you haven’t had a chance to see the latest Bond film Skyfall I highly recommend it. If you have seen it then you’re familiar with the concept of a biometric gun (also called a “smart gun”).   The idea has been around for a while but, essentially, it’s a weapon that requires a biometric (finger/palm print) scan and match from the owner in order for it to fire (other concepts include RFID chips and magnetic release). This is supposed to prevent another person from firing the gun and the idea has run the rounds in the gun control circles. It’s a swell idea on paper but, in real life it’s much more problematic.  Since it appears in a mega-blockbuster I thought you might want to keep a few things in mind should you choose to include a biometric gun in your next novel.

For law abiding citizens, a gun is a tool for self defense (sport too but that’s another topic for another day). When using a gun for self defense, simplicity of operation is preferred. The more complicated the system the more likely there will be a failure. All of us can conjure up images (from movies or television) of a crime victim grabbing a gun at the last possible second and shooting the bad guy. That may not be possible with a biometric gun due to a number of factors which I will separate into electronic, environmental, and situational categories.

First the electronics. Basically you have a digital scanner that reads the friction ridge skin pattern and compares it to the image on file. Then it has to determine a “match” before engaging the mechanical side of the gun to allow it to function. How long does this process take? How about in freezing weather? After being submerged? We’ve all had our laptop “freeze” up on us. It’s annoying but, we’re not fighting for our lives. Presumably the biometric gun operates with a battery of some type. Batteries can drain quickly in cold weather (ask any CSI about using a camera in a blizzard) and fail completely when wet. There are also concerns about impact damage. If the gun drops to the ground will the scanner crack? Will there be internal damage to the circuitry? When your life is at stake every second counts and you need a dependable mechanical weapon.

Aside form the electronics there are serious concerns about the “environment”. A biometric weapon requires a “clean” scan of the finger/palm print. Anything that interferes with the scanning will prevent the weapon from being fired. That means you can’t wear gloves (so much for cold weather use). Violent encounters/attacks also may result in bloodshed. If your hands are bloody then you can’t use the gun. Same goes for mud/dirt, grease, clothing, even water (firing underwater) may be problematic. One also presumes you have to have a flat even contact between your gun and skin which isn’t always possible. Hands can get cut open in a fight (defensive wounds) and the damaged friction ridge skin may not be recognized by the scanner. When you’re in a fight for your life you can get bloody, muddy, etc. and a finicky gun may cost you your life.

Lastly there are situational considerations. Imagine you’re in a public place when a bad guy comes in shooting. You get hit and go down injured. Your gun falls from your hand and a stranger picks it up as the bad guy advances on you. The stranger points your biometric gun at the bad guy, determined to save your life and his, pulls the trigger and…nothing. Well, not nothing. Presumably you’ll both be shot in a few seconds but you get my point. What if the guy that goes down is a police officer and you’re the by stander? Most likely the biometric gun won’t be “coded” to other friends and family and certainly not to a stranger yet, those may be the very people in a position to save your life or that of another.

So if you plan on using a biometric gun in your novel keep some of these things in mind. Gunfights are usually over in a few seconds. Of course, any one of these issues can add tension and danger to your plot line so feel free to use them. I can see your heroine trying to tear off her gloves as the rapist chases her through the park at midnight. Will she get them off before he catches her? Of course my heroine Sarah Richards will have a Glock so it won’t be an issue for her but, it might be an interesting challenge for your characters.

Camouflaged Weapons

Camouflaged weapons can be a real nightmare for police officers and CSIs alike. These are weapons that are “hidden” or concealed in some common or non-threatening object.  Some common “commercial” products over the years have been things like the pen knife, cane sword, or the pen gun. Edged weapons (knives and swords) are one thing but camouflaged firearms are a whole other danger. Thankfully they are pretty rare among criminals and most sales of legitimate items are to collectors. One main reason for this is that these weapons usually only fire a single shot.  That’s not too useful to your average criminal. Another reason is that it takes some skill (and time) to build these weapons even if converted from a legitimate product (like a pen). Still, it happens. I once saw a case of a motorcycle that had been modified to fire a single shotgun slug from the handlebar grip. The idea being that as an officer approached (roadside) the criminal could aim and discharge at close range. This is one reason officers are encouraged to approach motorcycles from the curb side (the handle/throttle is more difficult to modify on that side).

In the video below we see an example of a toy gun that was modified to fire a single shotgun shell. The selection of the modified weapon is important to note for fiction writers.  Toy guns like the Super-soaker are designed to look like toys. These toys are very common in the United States and most officers with kids have probably been “attacked” with one on a daily basis in the summer. That is what makes this weapon so dangerous. An individual armed with this camouflaged weapon could approach anyone (even an officer) without raising an alarm. Who could blame them? It’s a matter of conditioning. I think if you ask most police about concerns they may have with toy guns it would be the ones that are designed to look and feel like the real thing. Every cop has nightmares about shooting some innocent kid armed with one of these; but a Super-soaker?

As authors, we try to conceal plots, motives, and identities within the fabric of the story we weave.  Surprise is a wonderful mechanism to keep your reader engaged. In the real world these weapons can be deadly but in a novel they can cause a lot of nail biting tension. Readers don’t want everything in plain sight. They expect a little mystery and camouflaged weapons might be one of the tools you can use to give them what they want.

Will A Gun Fire Underwater?

I know all of you have been dying to know the answer to this question right? :) Well, today you’ll finally get your answer. I’ve got a posting here at the Crime Fiction Collective about this very topic including a cool video. Some of you may be very surprised to see what happens when you fire a gun underwater!

Future Forensics: Smart Bullet Finds Target at Over a Mile Away!

Here is an interesting story and video about a revolutionary bullet being designed like a cruise missile. When the cartridge is fired the bullet sprouts fins which control it’s flight path to the target. I doubt police will have to deal with this technology anytime soon but it opens up some interesting ideas for a science fiction crime story. The current technology is cool enough but what if your bullet actually “scented” the target like a bloodhound? I’ve written about the amazing capacity of bloodhounds in tracking human scent here and here. But what if a bullet could “scoop up” and analyze scent as a means of finding a target? Bloodhounds do it and scientists have used instruments for high volume air sample screening in atmospheric and environmental studies for years. By analyzing scent could a bullet be programmed to follow a person’s scnet or DNA which is constantly being shed in the form of skin cells. Could you literally pick a person out of a crowd?

Taking it one step further (and this is way out there but we’re talking science fiction) what if a bullet could be programmed to ignore “friendly” targets? That population of “friendlies” may be as small as family members or as large as a military division. Of course, a bullet can’t stop in mid air (or can it) and course corrections at 1100 ft/sec become increasingly difficult if not impossible as the range to target decreases but again, we’re talking fiction. This technology might be something to consider using in your science fiction novel under certain circumstances where you wouldn’t run into certain problems like crowds of people.

Another consideration is the purpose of the projectile. Maybe in your story it is designed for “tagging” or less-lethal incapacitation than it is for killing. In any event, I thought it was interesting and it got my mental gears engaged.

The Value of Firearm Ejection Patterns

White tent placards showing shell casing locations

A lot of researchers have studied what examiners refer to as “ejection patterns”. This is the arrangement and dispersion of fired cartridge casings found at a crime scene. The theory is pretty straight forward; cartridge casings will be ejected from a firearm in a predictable manner that will provide insight into the shooter’s position when firing. Unfortunately, the chaism between theory and reality can get pretty wide.  Semi-automatic, or self-loading, firearms are designed to extract and eject fired cartridge cases to make room for the next live cartridge in the magazine.  Most modern firearms are designed for right-handed shooters and will eject the cases to the rear and right of the shooter. Having said that there are some weapons designed for left hand shooters which eject to the left and still others that eject downward out the bottom of the weapon. The key function is to keep the spent casing from hitting the shooter.

The problem with the use of ejection patterns is that there are a lot of things that can and will influence the manner in which the casing comes to a final rest. First, the manner in which the weapon is held during the firing process. If the gun is held “sideways”, sometimes referred to as “gangster style” with the ejection port facing up, the casing will eject differently than if the weapon was held normally with the sights pointing up.  The elevation of the weapon is another consideration. Is the person shooting from the hip or shooting with the weapon at eye level (or both)? Then you have to consider the movement and orientation of the shooter.  Is the shooter firing straight ahead of them or to their right or left? Are they moving (running and shooting) or are they stationary? You may never know these things with certainty, especially if the weapon isn’t recovered. All of this is bad enough but we haven’t even begun consider the many factors.

Aside from the weapon design and how the shooter fires and moves there is the environment. Is the shooting indoors? If so, the casings may be hitting other objects like walls, furniture, chandeliers, etc. that can alter the “flight path” of the casing.  If the shooter is outdoors are there over-hanging branches from a tree? Is there a strong wind? We also have to consider the surface the casing lands on.  Surfaces like snow or a lush green lawn may help to “catch” the casing and allow for very little movement. Other surfaces like cement, linoleum, or tile may allow the casing to “bounce” and change direction. Then there is the slope of the surface. Envision a casing that hits a roadway versus one that hits on the sloped area of the sidewalk leading to the gutter. Think of a cartridge casing like a little football. We all know how unpredictable a bouncing path for a football can be right? Well, casings can act in a similar manner.

When all of that is said and done we still have to consider any “post-shooting” processes that may change the resting position of the expended casing.  Cartridge cases are small and can easily be moved if they are kicked, stepped on, driven over, or by other actions.  There are a lot of first responders like police, paramedics, medical examiners, even by-standers or family members that may also inadvertently move these casings before the CSI shows up on scene.

The above video shows both slow motion and normal speed ejections. Notice how varied the flight paths are for the same weapon with a static (stationary) shooter. Also, about half-way through the clip you will see one casing actually hit the camera and bounce back towards the shooter.

You might read references to police using ejection patterns in novels or see them on a television show but the analysis is not nearly as straightforward as they might seem. In fact, some studies have shown as much as 25% of casings don’t even eject in the manner or direction as designed. That’s not too surprising actually. Gun manufacturer’s don’t really care about exactly where the casings eject or how consistently they eject in the same manner as long as they stay out of the shooter’s face.  Now ejection patterns can provide some general insight into the general location of the shooter but you just have to be very careful about how far you take the reconstruction. So the key is to recognize the many influences that can vary the resting position of the cases.  If you want to have some fun with it you could have an expert rely too much on the locations of the casings only to find out later that they had been moved through some other action. That could really throw your analysis into a tailspin.

Components of a Shotgun Shell

Clockwise from upper left; gunpowder, No. 8 pellets, blue shotcup, and empty 12 gauge shotgun shell

Shotgun shells are similar to center-fire cartridges with one important distinction; the wad or shot cup. Shotgun shells come in a variety of calibers (such as .410, 20 gauge, 12 gauge which are the most common) and typically fire pellets instead of a single projectile. Having said that, there are shells designed to fire a single projectile called a “slug”. The size and number of pellets varies as well and are designed for specific uses.  Size 8 or 9 shot are small BB sized pellets used for target practice and small game hunting while larger shot such as 00Buck are used for home defense and predator hunting.

When a typical cartridge is fired at a crime scene the CSI might look for both the bullet and the cartridge case. The other component (powder) is generally burned up but can be found in a residue. But with a shotgun discharge the CSI may also be looking for the wad or shot cup . Most modern ammunition uses a shotcup which is a plastic “cup” with separate “petals” which fold away after leaving the muzzle and slow its forward movement (see photo). Older shotgun shells commonly used a wad which was a small fibrous disc of the same diameter as the shell. It’s kind of like a little padded sponge but without the holes and denser. Without a wad or shotcup the pellets would exit the muzzle with much les energy because the pellets can’t hold back the pressure as well as a solid projectile. Shotguns are smooth-bore weapons and generally do not have rifling which means the examiner can not do a traditional rifling comparison like they would with an expended bullet.

Various types of fired shotcups

Badguys will sometimes pick up their expended cases or shells (often referred to as “policing your brass”) but finding the shotcup would be very difficult as it can travel quite some distance from the muzzle (I have found them over 100 feet away).  Sometimes, if the muzzle is in contact or close contact with the victim the shotcup or wad may even be recovered from inside the victim at autopsy.  Now a firearms examiner can not link a shotcup to a particular weapon but examining the shotcup might reveal what type and size of shot was used and even the manufacturer of the ammunition. This might be important circumstantial evidence to consider when searching a suspect’s home, vehicle, or financial records.

Expended shotcup on ground

Author Arthur B. Reeve Part 1: Pushing Back the History of Forensic Ballistics

Guy Garrick Examines Evidence

When Americans think about the origins of forensic ballistics one name comes to mind: Col. Calvin Goddard. Col. Goddard was an amazing scientist who contributed greatly to the advancement of forensic analyses. His name will forever be linked with the St. Valentine’s Day Massacre in Chicago in 1929 where Al Capone’s gang murdered seven rival gang members. Col. Goddard performed the forensic analysis of the expended bullets to link them to the murder weapons. But, did forensic ballistics begin with Col. Goddard as many believe? The answer is an emphatic no.

Enter the novel Guy Garrick: An Adventure with a Scientific Gunman (1914) written by Arthur B. Reeve.  Mr. Reeve was probably best known for his “Professor Craig Kennedy” series but this book is remarkable for the inclusion of forensic ballistic and impression evidence.  Fiction authors presenting forensic themes to their stories is hardly anything new. Sir Arthur Conan Doyle is one prime example.  Without taking anything away from the genius of these authors it is obvious that they drew their information from the science and scientists of their time. In fact, the fictional detective Guy Garrick references the work of Dr. Victor Balthazard and Alphonse Bertillione on several occasions.

This posting is not intended to take away from the contributions of Col. Goddard but to expand the origins of the science to others who richly deserve part of the credit.  We may never know the exact source(s) Arthur Reeve relied upon for his research but we do know that the knowledge preceded the St. Valentine’s Day Massacre by more than 15 years.  In fact, a number of experts were examining forensic ballistics at the end of the 19th Century. Consider these fascinating Garrick excerpts from the novel.

“Well, Dr. Balthazard, the French criminologist, has made experiments on the identification of revolver bullets and has a system that might be compared to that of Bertillion for identifying human beings. He has showed by greatly enlarged photographs that every gun barrel leaves marks on a bullet and that the marks are always the same for the same barrel but never identical for two different barrels. He has shown that the hammer of the revolver, say a center fire, strikes the cartridge at a point which is never the exact center of the cartridge, but is always the same for the same weapon. He has made negatives of bullets nearly a foot wide. Every detail appears very distinctly and it can be decided with absolute certainty whether a bullet or cartridge was fired by a certain revolver.”

“In short..the ends of the firing pins are turned and finished by lathe by the use of tools designed for that purpose. The metal tears and works unevenly so that microscopical examination shows many pits, lines, circles, and irregularities. The laws of chance are as much against two of these firing pins or hammers having the same appearance under the microscope as they are against the thumb prints of two human subjects being identical.”

Fascinating stuff…more to follow.

The Ol’ Gun was Recently Fired “Test”…Not!

Gun recovered at crime scene

I’m sure you’re all familiar with this scene. The detective finds a gun in the suspect’s house, or car, or wherever and after glancing at it or possibly sniffing it they proclaim “Ah ha! This gun was recently fired”. I’m not sure how this idea ever took hold but it has become so prevalent that a lot of authors and readers might actually believe it.  Now, it would be awesome if we could actually determine such a thing but, alas, we can’t.  Nor can we tell if a gun was “recently” cleaned.  It sure does make for a memorable statement though.

We can tell if a gun has been cleaned since last being fired. We can determine that a gun is clean and that it may have excessive gun oil or something like that but we can’t quantify the duration of that condition.  Now this could be informative if police stop a guy in the vicinity of a shooting and he’s carrying a gun. If the gun is “clean” they might eliminate him as the shooter. However, this would assume that he didn’t use another (second) firearm or that he didn’t use something like a Boresnake to quickly wipe the barrel.

Most firearms examiners will run a new cleaning patch down the barrel before test firing the weapon. This maycapture things like unburned gunpowder (useful in comparing to GSR  or fired cartridges found at the crime scene), blood spatter, or other trace evidence which may help link that gun to the crime. But CSIs or detectives can not tell that a gun was recently fired (or not fired) simply by looking at it.

Is it Strange to Find a Gun in Hand?

Excuse the pun, but that’s a loaded question.  Some say yes, some say no and they’re both right.  As with a lot of things CSIs examine, we need to look beyond the “binary” condition of the evidence and consider factors which may influence that condition.  In other words, it’s not as simple a question to answer as it may appear. First and foremost we must decide upon a definition of “in hand”.  For our purposes let’s say that “in hand” means that the gun in some way is touching the shooting hand.The fingers may or may not be in the trigger guard, the grip in the palm, etc. The reason I leave the definition broad is that in the course of my career I have heard officers, DAs, etc describe a gun as being in the victim’s hand when it was barely touching it.

Gun in hand

As you can imagine; shooting a gun is a violent event.  The most significant aspect of that firing is the recoil (force generated by the discharge of the cartridge).  Larger calibers generally generate more recoil than smaller ones. Additionally, a living person can absorb recoil to varying degrees but a deceased person lacks the muscle control to do so. Firearms are also heavy and will fall with gravity until stopped. So, considering all these factors. the most important are body position, followed by firearm type.

Imagine a man sitting in a folding chair and shooting himself in the head with a .45 caliber pistol. His arm drops to his side and without muscle control it is very likely that the gun will fall from the hand and onto the floor. Now consider the same shot but instead of sitting upright in a chair, the man is laying in bed.  If the gun is only falling 2-3 inches and onto a soft surface (like a bed) then it becomes more likely the gun will remain in the hand to some degree. Now consider instead of a .45 the gun in question is a .32 caliber. Less recoil, probably lighter gun, less chance of falling out right?

It’s not to say that a gun in the hand should never be considered suspicious. Certainly, if we believe that a scene has been staged we may expect to find the gun placed in the hand (more on this in a later post). But the presence of a gun in the hand in not , in and of itself, evidence of homicide.  We have to look at a number of other factors before concluding that it shouldn’t be in the hand. Sometimes we may even have to conduct role playing exercises to test these factors.

So when writing a scene in your book where gun placement is important to your story think about how recoil, gun weight, and body position might affect the final resting place of that gun.  Certainly, if you want to add some mystery to a scene you could have characters argue different positions regarding the importance of the gun being in the hand. Placing unwarranted importance on the gun position can lead the investigation astray and may even implicate an innocent character.

How Criminalists “Touch” Evidence

This information might be better suited for a screenplay but I think you’ll find some value in it for novels as well.  Forensics is about observation. Good forensics is understanding what you’ve observed.  Try an experiment I’ve asked a number of interns to complete. Over the next few weeks watch how people handle certain objects. To simplify things you can watch for a certain activity (like opening doors) each day.  How do people enter through a door?  Do they grab the handle going in? What about coming out?  If they hold the door open, where do they grab it?  Don’t just look at buildings, watch people getting in and out of vehicles too.

The next day watch how people hold a glass or bottle while drinking from it. Do they grab it in approximately the same place each time? Do they clasp it with all of their fingers or just a few? The watch people reading a book, reading a piece of paper, or looking at a photograph.  It may sound kind of goofy but as criminalists we want to understand how people handle things because that tells us where we expect to find fingerprints. More importantly, it tells us where not to touch. This only applies to smooth areas that can hold a fingerprint in the first place. If the area is textured (like the grips of some pistols) or if it is very small like the tab on a beer can we can safely assume no comparable fingerprint is there.

Notice how I handle the beer can by the tab while dusting for fingerprints

Think about it. If we handle objects in the same manner that the average person does then we run a greater risk of smudging the very evidence we’re searching for.  That’s the last thing we want. For example, if I’m entering a crime scene (say a bank) through the door I’m not going to just grab the handle and yank it open. If I have to grab the handle I’ll grab the top corner or edge of the handle to get the door open a bit and then I may grab near the top of the frame to open it all the way. We never want to touch where the suspect likely touched.

After you’ve spent a week or so watching how people handle objects ask yourself how you’d do the same activity without touching the same areas they did.  Many times we have to handle objects by the edges or by any area too small to hold a fingerprint. It makes our job a little more challenging sometimes but the reward can break a case wide open.


Get every new post delivered to your Inbox.

Join 372 other followers

%d bloggers like this: