Monthly Archives: July 2011
The other night I was watching a movie called Takers and something came up that has always been a pet peeve of mine; detectives who work on “everything”. It may seem like a minor thing but in the interest of being accurate authors should recognize that detectives don’t typically run from crime scene to crime scene at will. Most detectives have specialized skills and are generally assigned to squads like “Robbery/Homicide”, “Property Crimes”, “Narcotics”, “Vice”, etc; especially in big cities. This is because each of these crimes have particular elements that detectives spend years learning about.
So in this movie, Matt Dillon’s character and his partner start out the morning by busting up a narcotics deal and getting in a shootout with the drug dealers and then after leaving that scene respond to a major bank robbery in which five men with military gear and automatic weapons get away with over a million dollars. Actually, I need to do a posting on what happens after an officer involved shooting but for now let me continue. The problem with this is that narcotics detectives would never be assigned as lead detectives on a bank heist. It was as if, in city of over a million people, these were the only two detectives on duty!
Technically bank robberies fall under the jurisdiction of the FBI however they routinely have local law enforcement process the robbery scenes; especially after 9-11 when FBI priorities shifted more towards counter-terrorism. That’s not to say an FBI agent wouldn’t respond to the scene to interview witnesses though. The important thing to remember is that detectives are assigned to specific units and it is unusual for them to investigate crimes outside that squad (unless there is a connection in the case between say drugs and homicide). Even then they would only be a part of the team and not supersede the other detectives.
One key finding in any fire death is whether the victim was alive during the blaze. If the victim was already dead it may indicate foul play (homicide) as opposed to suicide or accident. There are two reliable indicators that speak to a person’s vitality during fire events. The first is the measurement of carboxyhemoglobin in the bloodstream. This occurs when the hemoglobin binds with carbon monoxide instead of oxygen thereby “starving” the bloodstream of necessary oxygen. Some studies indicate that nearly 50% of all fire victim’s have lethal levels of carboxyhemoglobin.
The second indicator is the presence of soot in the airway. This is only determined through autopsy and a detailed examination of the airway. The presence of darkened soot in the airway indicates that the person was breathing during combustion. Dead people don’t breath and thus can not draw soot into the airway.
Using this information in your storyline can be pretty straightforward. One option is to have a house fire in which a victim died but the scene was staged by setting the fire to mimic an accidental ignition (maybe a space heater set up next to a blanket). If an autopsy wasn’t conducted and the local Coroner ruled it an accident then there wouldn’t have been any examination of the airway. You could then have the body exhumed or examined prior to burial to find evidence that the victim was already deceased. Of course it’s possible to have a person die prior to an accidental fire (in theory) so you’ll need to introduce a motive for the killing and perhaps some evidence found on the suspect. This might include fire damaged clothing (burned clothes, melted out soles of shoes, etc.).
Advertisers will tell you that words matter. Well, nothing could be truer in the case of “bullet-proof vest” or body armor. These are the protective vests that many military, law enforcement, private security, and even civilians wear to protect their vital organs from certain calibers of bullets. Generally they are categorized as either “hard” (ceramic style worn by military) and “soft” (Kevlar fabrics worn by non-military). Notice that no where in the description of this protective wear is the term “knife-proof”.
That’s because soft body armor is designed to resist blunt, or crushing, trauma. The Kevlar fabrics are layered and weaved in a way to spread the force of the bullet’s impact over a large surface area thereby lessening the traumatic effects felt by the person wearing the vest. These vests can stop most common handgun calibers but are still vulnerable to many rifle cartridges. The vests are also vulnerable along the seams and edges.
Knives, however, produce cutting damage; not crushing damage and therefore can penetrate many vests. This fact eludes some members of our society I like to call the “Jackass” crowd. These are they types that love to videotape themselves engaged in really dangerous and stupid acts in the name of “entertainment”. They are the kids that put an apple on their heads and ask you to shoot it off. There are plenty of home videos on line to watch but I don’t want to post them here. Suffice it to say, these vests sometimes provide a false sense of security to the wearer.
Now there are protective vests which are designed to be “knife-proof” but they are not as resistant to bullet penetration (although most can withstand a 9mm bullet). These vests can be very popular in prison environments where sharp weapons can be made by prisoners who do not have access to firearms. The belief that bullet-proof vests can stop knives is not rare in the world and as a writer you may want to keep that in mind. If you have acharacter who gets stabbed while wearing a vest they can still suffer serious injury. One way you could add some suspecse is to have a badguy wearing a vest break into a home to assault the resident. The homeowner could shott the intruder multiple times running out of ammunition but believing they have stopped the threat. Then when the badguy gets up they have to resort to using a knife but the badguy mistakenly believes his vest will protect him and charges the victim.
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.
So I’m reading an excellent book entitled Blood Trail by C.J. Box and there’s a part where the protagonist Joe Pickett finds the victim of an apparent gunshot suicide. The interesting part is that the victim had two gunshot wounds to his head. The author does a great job describing several theories of how that might happen with good dialog between characters and I thought I should talk a bit about this phenomenon. I don’t know of any good studies on the frequency of these events so I’ll just say that while they aren’t common, they aren’t rare either. In the course of my career I’ve investigated maybe two dozen or so and I’ve read papers on many more.
At first blush a multi-shot suicide might raise considerable suspicion of foul play (which it could be). Technically, there are two types of multi-shot suicides. One in which the victim has multiple gunshot wounds and one in which the weapon may have been fired multiple times including at least one into the victim. It sounds unbelievable that a person could shoot themselves more than once but there are a few things investigators need to consider. The first is weapon caliber. The larger the caliber, the less likely they can shoot themselves more than once. This is especially true with long guns like rifles and shotguns. On the other hand, I’ve seen reported cases where a person shot themselves just over a dozen times with a .22 pistol. That could never happen with a .30-06 hunting rifle.
The second consideration are the locations of the bullet holes. Not surprisingly, people don’t get too many chances to practice this sort of thing. If your victim is unfamiliar with firearms they may decide to fire a “test-shot” or two before working up to the fatal wound. Most of the time these shots are into the ceiling, bed, floor, or wall but occasionally the victim will shoot themselves in a “non-vital” area like the thigh. With any luck, a wound like that might change their mind for the moment and persuade them to call for help. If they don’t, the multiple shots can look very suspicious.
In your novel you might consider using this type of event to create the possibility of murder. Imagine finding a victim in a city park with several cartridge casings around them and a bullet wound to the temple. Wouldn’t that look like a murder, even if the gun was on scene? It may look even more suspicious if the gun were still in their hand. But what if your CSIs later excavated the ground and found the bullets all traveling straight down from the victim’s position (as if they pointed the gun downward and fired off a few shots)? That might swing the investigation back the other way. No matter how you use a multi-shot event it can undoubtedly leave your reader turning pages to find out what it all means.
As to what really happened to the victim in Blood Trail, you’ll just have to read it to find out!
Unlike the things thieves typically steal, such as jewelry, money, electronics, etc., vehicles tend to take on the “personality” of the suspect who stole it. Obviously this is only true when the vehicle is used for a period of time. Taking a car directly to a chop shop is a different deal altogether. Believe it or not, car thieves don’t always steal high end cars. Most of the time they steal your garden variety sedan like a Honda Accord. And the longer they drive it the more likely they will leave behind important clues.
This is one reason investigators like to show the original owners the crime scene photos so that they can identify the things that are supposed to be there and those that are foreign. They can tell us when there is new damage too. As crooks drive a car they can change the seat position or the radio stations. They can leave cigarettes, clothing, drink cups/straws, or gum that can yield their DNA. In addition to DNA and fingerprints they may leave behind trash that may tell us where they have been.
Car thieves sometimes visit gas stations, retail stores, restaurants, and banks all of which may have surveillance footage of the bad guy. If the crook leaves a receipt behind it can tell us exactly where and when to look for that footage. Surveillance tapes might also reveal other suspects like a girlfriend who may be more recognizable than the suspect.
Sometimes investigators find evidence like credit card receipts, photographs, or personal items linking the suspect/vehicle with another crime. Crooks sometimes steal vehicles to commit another crime (classic getaway vehicle) so finding these items may help investigators build a better profile for the suspect’s activities during the time the vehicle was missing. They might have several license plates in the trunk or stolen items from several residential burglaries.
This video has nothing to do with forensics but it is such a good example of what can happen when professionals ask blind questions. I’ve been on the receiving end in court on a number of occasions. Trials are a series of complex arguments stacked upon each other, so it’s understandable when a lawyer veers a little off track. But when that happens, it can be like watching a train wreck. As a witness, you can actually watch the build-up. It begins with a pause, an extra glance at their notes, or widening of the eyes. That’s the moment they should have waited but instead rushed headlong into the unknown.
It happens to prosecutors and defense but typically the defense attorneys are more prone to it in my experience. Probably because they are looking for any scrap of reasonable doubt they can toss to the jury, and they get a little excited when they think they have a “gotcha” moment. I once had an attorney challenge my expertise as a footwear examiner in open court. I was sure he remembered me but apparently not. Imagine his surprise to learn that he had hired me four months earlier to give a presentation on footwear evidence to a professional association of fellow attorneys. Yikes!
During a murder trial a prosecutor once asked me what test I had used to determine that a light was on when I arrived at the scene. No kidding. How can you possibly answer that without making him look like a dope? In another murder trial the defense attorney begin my voir dire (questioning the witness to challenge their expertise basically) by saying “So you’re a forensic entomologist. I didn’t even know that was a science” to which I promptly replied “Yeah…we’ve got text books and everything”. It got a good laugh out of the jury and I think even the judge smirked a little, but how did he expect to challenge my expertise after admitting he didn’t even know that field was legitimate?
I guess the point is not to share war stories but to remind you that these gaffes can add a lot of humor or tension to courtroom dialog. It happens to the best of people and has more to do with impulse control than intelligence. Most of these attorneys are a heck of a lot smarter than I am, they just got caught up in the moment. So consider adding in a blind question or two and watch how it can transform a character from a hero to a zero in mere seconds.
I got a great question from a subscriber asking how bodies are recovered from bodies of water. There are some procedures many investigators follow when removing a body from the water. Some agencies may have policies particular to their local conditions so I suggest if your story is set in a particular city you might contact the medical examiner or coroner or dive team in that area to check on the policies they use. Certainly, the methods used in stagnant water (pond) may be different than those used in a fast moving river.
Additionally, there are safety issues, equipment requirements, and deployment procedures which will vary from scene to scene. Many local/state police or fire departments have certified dive teams trained in the proper recovery of bodies from water. These professionals are a great resource for consultation. Having said all that, here are some general guidelines investigators follow when removing bodies from water.
- When possible, victims are photographed while in the water. Care must be taken not to handle the body too much (so that the possibility of altering evidence is minimized). Obviously bodies have to be handled but care can be taken to ensure evidence is not lost. Submerged bodies may require the use of an underwater camera.
- When possible, bodies are placed into a body bag before being removed from the water. This is done to minimize the risk of losing evidence which might get dislodged while removing the victim from the water. Bodies in a submerged vehicle are often brought up still inside the car for this reason as well.
- Sometimes investigators have to remove evidence before removing the body from the water. This happens when there is a risk of losing specific items as the body is moved. Things like items used to weigh down the body, items in loose pockets or waistband, or clasped in the hands might all be at risk of dislodging while getting the body into the body bag.
- Last, the location where the body is initially found has to be marked for subsequent searching. Bodies can certainly travel many miles in certain bodies of water but you have to have a place to start.
This is an extremely brief and general posting but I wanted you to be aware that body recovery from water has special considerations. You can’t just hoist a body from the water or drag them onto the beach. Although this certainly can happen when citizens find bodies and attempt first aid. If water recovery is a central theme to your novel I strongly suggest you contact a local certified dive team so they might help you focus the details of your story for that specific body of water.
This is one of those articles that is probably a little too specific for most story lines but it is a great example of how a “one size fits all” solution doesn’t exist in evidence processing. I’ve written before about the use of Ninhydrin as a common chemical reagent used to process papers for fingerprints. Most of the time Ninhydrin produces excellent results. There are basically two methods to using the Ninhydrin reagent. After treating your paper evidence with the reagent you can either allow the prints to develop over night or you can accelerate the development with the application of heat and steam (usually with a steam iron).
You’re probably most familiar with thermal paper products from the numerous receipts from cash registers, credit card devices, toll booths, and gas station fuel pumps. Chances are good that you have a few in your purse or wallet right now. Thermal paper is with a chemical that changes color with the application of heat; and therein lies the problem. If you use a steam iron to accelerate the development of fingerprints you will turn the entire sheet black.
Most rookie CSIs only make this mistake once, and after the paper turns black the effects can not be reversed. This can pose some real problems for an investigation especially if the receipt wasn’t photographed or photocopied prior to testing (both of which are pretty common CSI practices). Receipts can provide some important clues to an investigation. They may have names, credit card #’s, and time specific locations of the suspect. This information can be more valuable than a fingerprint, even if the card is stolen.
Say you recover a stolen vehicle and find a receipt inside that was generated while the car had been stolen (maybe during a trip thru a fast food drive up). It would be nice to develop a fingerprint on that receipt because it may lead to the identification of a suspect (assuming they have been fingerprinted). But, knowing that the bad guy was at McDonald’s at 5:45PM last Tuesday means you may have him and other suspects on surveillance footage. But if the data is lost before it can be evaluated you may have lost the best clue in the case and the fingerprint along with it.
So one way to use this in a story is to have a headstrong or impatient police officer decide to process a thermal paper receipt themselves without waiting for a CSI. After all, CSIs are not always available the moment you want them there (if there are any command staff people reading this I know you are in shock right now. Please take a moment, sit down, and breathe before attempting to continue). If the officer has never worked with this evidence before (some police officers can and do limited processing of evidence) they may not think to copy the information first. When that paper turns black they will have a real panicked “oh Sh%t” moment.
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.