Reference Citation: Schiro, G. Shooting Reconstruction – When the Bullet Hits the Bone. Southern Lawman Magazine, Fall 1998.
George Schiro, MS, F-ABC
At some point in his or her career, an investigator may have to examine a shooting incident. The shooting may be part of a civil matter, such as a hunting accident or a weapon malfunction, or it could be a criminal matter, such as a homicide or a suspected suicide. Before starting the investigation, the detective must ignore any misinformation or mistaken notions learned from folklore and television shows. The investigator must gather reliable information from valid resources and knowledgeable consultants. A detective's experience with a variety of firearms and firearms training can also be valuable in a shooting examination.
The detective must prepare by researching several areas before attempting to reconstruct the circumstances of a weapon discharge. This research may involve extensive reading, viewing videotapes, interviewing witnesses and participants, firing the suspect weapon, examining and documenting the scene, and collecting evidence. The investigator may also have to consult with firearm training instructors, armorers, firearms manufacturers, crime scene investigators, ballistic wound experts, pathologists, firearms examiners, and even forensic psychologists, particularly when searching for possible motives in a suspected suicide investigation.
Physical evidence is produced whenever a firearm is discharged. This evidence can consist of the firearm, the cartridges, the projectiles, the cartridge cases, primer residue, gun powder residue, the projectile flight paths, the area surrounding the shooting, blood spatter patterns, and the shooting victim. The person, living or dead, who is suspected of firing the shots can also provide evidence that may be relevant. This information and evidence must be gathered and assimilated to produce an accurate reconstruction. The investigator must also be aware of shooting reconstruction limitations. All of the elements must fit together in a logical sequence, but the investigator must have an open mind and may have to allow for several scenarios based upon the evidence. The detective must be cautious and not interpret the incident any more than the evidence allows. Depending on what elements are present, the reconstruction may not provide any information of value.
After the investigator has a thorough background in the various aspects of shooting investigations, he or she should gather as much information as possible about the incident. This information includes witness statements, victim statements, and suspect statements. These statements may lead to evidence not readily visible or prevent the destruction of the shooting evidence. This information can also be compared with the shooting evidence to determine which statements are more accurate. In some cases, the detective may be contacted after the shooting has already been investigated by a law enforcement or other investigative agency. In these cases, the investigator may be limited to the documentation and evidence collected by the other agency. If time has passed since the shooting, then the original scene may have been altered in some way and may not be an accurate representation of the original shooting scene. The investigator will then have to rely on taken statements, crime scene notes, videotape, photographs, sketches, crime scene reports, and crime lab reports. If these materials are thorough, then the investigator will have enough information to conduct an independent investigation of the shooting incident.
If the detective is a principal to the original investigation, then he or she must take a slow and methodical approach to the scene investigation. After gathering as much information as possible about the scene, the investigator conducts a walk through of the scene and surrounding area. The walk through is completed in a logical manner and includes the obvious areas associated with the shooting as well as areas where evidence may be concealed. During the walk through, the scene must be thoroughly searched, particularly the ground, since this is the area that is walked on and most evidence is found on the ground. Any evidence can then be marked or noted so that it will not be disturbed. The walk through also allows the investigator to form a written or mental plan to document and collect the evidence.
After the walk through, the investigator must document the evidence before collecting it. Documentation consists of notes, videotape, photographs, and sketches of the scene. The evidence must be documented from its initial location and recovery by the detective to its release from the detective's possession. Documentation is especially crucial to a shooting reconstruction because it demonstrates the reconstruction elements to a client, attorney, jury, etc. A chain of custody must also thoroughly document the movement of the evidence, the security of the evidence, who had possession of the evidence, and when the evidence was in that person's possession.
Videotape is an ideal medium for documenting evidence. Because a video camera can mimic movement of the human eye, it is a more natural viewing medium than photographs. The camera moves freely and gives the viewer the perception of moving through the scene. The camcorder also records the evidence and its relationship to other structures at the scene. If the investigator chooses to use videotape, then he or she must know how to properly use the camcorder and should routinely practice by using it in non-critical situations before using it to document evidence. When documenting evidence with a video camera, the detective must move the camera slowly and hold evidence in the viewfinder for at least five seconds before moving the camera again. If the investigator decides to use the audio portion of the videotape to record a narrative of the scene, then he or she should just record observations and not draw any conclusions on the videotape. The videotape should contain overviews of the scene, medium shots showing the relationships of evidence to the surrounding structures and other evidence, and close-ups of the evidence at the scene.
Photography is another essential tool for documenting the scene and the evidence. While photographs demonstrate only a narrow view when compared to the human eye, photographs capture much greater detail than videotape. Photographs are also valuable for direct comparisons. For example, actual size photographs (also known as one-to-one photos) of bullet holes can be compared directly to bullets fired from a suspected firearm. The same rules that apply to videotape apply to photography. The investigator must be thoroughly familiar with his or her camera and he or she should practice taking pictures whenever possible. The photographs should also contain overviews of the scene, medium shots showing the relationships of evidence to the surrounding structures and other evidence, and close-ups of the evidence at the scene. If one-toone photographs are required, then a scale or ruler must be incorporated in the photos.
A sketch is another means of documenting evidence. Photographs provide limited information because they are two dimensional images of a three dimensional area. As a result, photographs can distort spatial relationships of photographed objects making them appear closer together or farther apart than in actuality. Sketches are very important to a shooting incident reconstruction. The sketch is the only way to accurately portray the horizontal, vertical, and depth components of any projected bullet trajectories. The sketch also accurately represents the spatial relationships between evidence.
The sketch of the scene could be drawn as if one is looking straight down (overhead or plan sketch) or straight ahead (elevation sketch) at the area in question. A rough draft is drawn first on graph paper with so many squares representing so many square feet or inches. Measurements between objects and/or structures are then taken at the scene. These measurements are proportionately reduced and the objects are drawn in the rough sketch. A final sketch can then be made using inks, paper and a ruler, or a computer. The rough sketch must be retained and preserved by the investigator in case it is needed at a later date.
After the evidence has been thoroughly documented, it is evaluated, properly collected, and preserved. The investigator must know what he or she wants done with the evidence and what experts will be called to assist the detective in the reconstruction. The primary piece of evidence is the firearm or firearms involved in the shooting. An examination of the firearm can provide information useful to the shooting reconstruction. Notes should be taken on the condition of the gun as found without touching the weapon, for example: hammer cocked or uncocked; safety on or off; gun jammed; magazine in or out, etc.
Before anything is done with the weapon, the weapon must be made safe, preferably by removing the magazine and any cartridges that may be present. If rounds are to be removed from the cylinder of a revolver, then the location of the cartridges and cases within the revolver must be noted. One of the chambers can be marked on the cylinder as number one and the other chambers can be numbered sequentially. Each cartridge or case is then placed in an individual envelope labeled with its chamber number. While rendering the weapon safe, the investigator should use gloves and he or she must handle the weapon on the textured surfaces and minimally touch the gun's smooth surfaces so fingerprints will not be disturbed. The investigator should note what steps were taken to make the weapon safe. Once the weapon is safe, it can be processed for prints at the scene or it can be transported elsewhere for processing.
The gun can provide other information crucial to the investigation. A complete examination of the gun's functionality must be conducted to determine if a malfunction could have caused the shooting. A test must be conducted on the trigger pull to determine how many pounds of pressure is required to fire the gun. By examining the ammunition in the cylinder of a revolver and the magazine of an automatic or semi-automatic weapon, the detective may be able to determine the number of shots fired. The investigator must make every effort to account for all of the shots fired by examining the weapon, accounting for all of the cases and bullets, and tracing all of the bullet trajectories. The firearm can also be linked to specific shots fired by comparing the bullets and cases to reference ammunition fired from the weapon. The weapon must also be examined for any other evidence, such as blood (especially in the barrel), hair, bone fragments, fibers, paint, etc. This evidence may link the gun to a person or a place and it could indicate how close the gun was to the target when fired.
While cartridges are not a major factor in a shooting reconstruction, they can be linked to a specific lot of ammunition that may be in a suspected shooter's possession. Cartridges found at a shooting scene can be examined for manufacturing marks, such as cannelures, that may also be present in a suspect's ammunition. If the cartridges in a weapon appear to be from the same manufacturer, then that ammunition's age and storage conditions may provide information concerning the bullets’ performances. For example, if a weapon is heavily oiled with penetrating oil and this oil eventually seeps into the cartridges, then this would effectively reduce the bum rate of the gun powder and make the round much slower. This could affect the bullet's flight path and depth of penetration.
The cases found at a shooting scene can also provide valuable information. The cases will usually give the most accurate account of the number of shots fired because the cases will stay in close proximity to the gun, although they can be difficult to locate. By counting the number of cases in a revolver cylinder, an accurate count of shots fired can also be determined. The cases can be linked to a specific firearm through tool marks transferred from the gun to the case when the cartridge is fired.
Whenever dealing with a weapon that ejects cases, it may be necessary to determine the firearm's ejection pattern. While standing on a surface similar to the shooting scene, 20-100 rounds are fired from the weapon. The distances of the cases from the firearm are measured and the area of the ejection pattern is determined. This information coupled with case measurements from the sketch can approximate the shooter's position when those shots were fired. In conjunction with bullet trajectory projections, the place from which the shots were fired can be determined with a high degree of probability.
Residue from the ammunition's primer can also provide reconstruction information. Whenever the firing pin strikes the primer on a cartridge, the primer explodes and explosive residues are produced. These residues will deposit on the gun, the shooter's hands, and the victim's hands, if they are in close proximity to the weapon when it is fired. A suspected shooter's hands can be swabbed or a tape lift can be collected. This swab or tape lift can be analyzed for these residues to see if the suspected shooter had recently handled a firearm. Some uncertainty is associated with this type of examination because not all weapons will deposit primer residues in detectable quantities.
If a shot is fired close to a target, then gun powder residue can give an accurate determination of the distance between the firearm and the target. A contact shot to a target produces tearing, a large amount of burning, and unburned gun powder particles deposited in the bullet tract. A near contact shot will cause burning around the bullet hole and a tight pattern of unburned gun powder particles. As the firearm moves farther away from the target, there will be little to no burning around the bullet hole and the unburned gun powder particle pattern will generally get wider. As the firearm is moved even farther away from the target, no unburned gun powder will be seen around the bullet hole. Test patterns can be made from the suspect weapon and compared to the patterns found at the shooting scene to accurately reconstruct the distance of the firearm to the target. If a revolver is held close to a parallel surface when fired, then escaping hot gas from the cylinder gap and barrel will deposit on the surface in a manner that allows the length of the barrel to be accurately measured.
The area surrounding a shooting incident can also provide reconstruction information. The area may have bullet holes that will allow projectile trajectories to be determined and can also lead to the recovery of bullets. The area may have intervening structures in the shooting scene that when combined with the projectile trajectories place the shooter in a particular area or exclude him or her from standing in certain areas of the scene. If any doors or other movable structures have bullet holes, then their positions at the time of the shooting may be determined. Bloodstain patterns at the scene may show if the parties were injured and their movements could be traced by examining any surfaces upon which they bled. High velocity spatter may show the victim's position when shot, and blood pools may show where the victim bled out or if the victim's body had been moved in attempt to alter the scene.
In much the same manner, a victim's wounds may provide information relevant to the shooting reconstruction. The wounds may show distance determining characteristics, such as tearing, burning, and unburned gun powder particles. A wound's depth penetration may give an indication of the projectile's speed at the time of impact, especially in situations where the gun was fired from a great distance away or the bullet struck an intervening object before striking the victim.
The most accurate and easiest method for determining the estimated location of a shooter is by projectile trajectory determination. This is accomplished by finding a place where a bullet passed through two surfaces or one thick surface. Bullets usually act in a reproducible manner. They travel in a straight line for relatively short distances (a bullet trajectory is actually an arc over a long distance). Because they travel in straight lines, their trajectories can be projected by running a straight line through the bullet holes. This line represents the line along which the shooter must have fired the gun. The goal of the investigator is to determine the position along this path where the shooter was more likely to be located. For example, if the line is projected out to 15 feet and the height of the line at this point is ten feet, then it is obvious that the shooter had to be closer than 15 feet.
While most bullets travel in a reproducible straight line to the target, the investigator must be cautious. Bullet flight paths can be affected by the firearm, the age and/or the storage conditions of the ammunition, the angle of the bullet flight path, the target material, and any intervening objects in the bullet flight path. These conditions could cause a deviation from the straight line path. Some tell-tale signs of this are ricochet marks, multiple holes from a single round of non-shotshell ammunition, and "keyholing." Keyholing is when a bullet does not make a clean round hole, but the hole appears to be a profile of the bullet. This is caused by the bullet tumbling which means that the velocity of the bullet was slower than normal. Keyholing is seen primarily when the bullet strikes an intervening object that destabilizes the bullet before the bullet strikes the target.
In addition to taking overall, medium range, and close up photos of the scene, the investigator must take close up photos of all projectile holes with a scale (a small ruler or ABFO scale). The investigator must also note and photograph with a scale any artifacts associated with the bullet holes (for example, tissue, fibers, unburned gun powder particles, fragments, muzzle blast/cylinder gap residues, etc.). The investigator should then collect and/or test these artifacts.
If expended cases and/or a weapon are at the scene, the investigator should attempt to correlate the number of bullet holes with the number of shots fired. The trajectories can then be determined by using string, dowels, and/or a laser in conjunction with an angle finder. These are projected through the center of the bullet holes to reconstruct the bullet flight path. The investigator must be cautious, especially when attempting to make a determination from a single bullet hole. The thicker the single bullet hole substrate, the more accurate the trajectory determination. The investigator must also consider anything that could cause the bullet to deviate from the straight line path.
After the trajectories are determined and demonstrated with strings or dowels, the investigator should photograph and/or videotape someone along the flight paths to show the potential positions of the shooter. After these photos the detective must collect and record measurements of the straight line paths to determine the horizontal and vertical angles of the shots. Repeat the measurements to insure accuracy. If a laser and an angle finder are used, then the vertical angle can be read directly from the angle finder; however, measurements should be taken to find the horizontal angle and to confirm the angle finder's vertical angle measurement. If a laser and angle finder are not available, then the angles will have to be calculated from the measurements using trigonometry and confirmed by the Pythagorean theorem. Proportional sketches must then be drawn demonstrating the horizontal, vertical, and depth components of the bullet flight paths.
When the trajectories have been determined and documented, the bullets can be located and removed. The bullets must be examined for any evidence, such as blood, fabric, glass, hair, etc., that may be adhering to them. These materials can be collected and analyzed to show the items a bullet passed through. Any bullets collected may also be matched back to a particular firearm or to a lot of ammunition. If an investigator is called to examine a shooting incident, then the investigator must become very familiar with firearms and firearm evidence. The detective should take a holistic approach to the investigation and make sure all elements of the investigation are logical and supportive of the other elements. Only then, will the investigator be able to make an accurate assessment of the situation and reconstruct the shooting as close as possible to the actual events.
Thanks to my co-workers Joe Briso1ara and Pat Lane for their comments and suggestions.
AFTE Journal, the official publication of the Association of Firearm and Tool Mark Examiners, Jerry Miller, Editor, Atlanta Forensic Science Laboratory, 2600 Century Parkway, NE Suite 410, Atlanta, GA 30345
Deadly Effects: Wound Ballistics, Videotape, ANITE Productions, Pino1e, CA
Deadly Weapons: Firearms & Firepower, Videotape, ANITE Productions, Pino1e, CA
Haag, Lucien C., Forensic Firearms Evidence: Elements of Shooting Incident Investigation, Videotape and Handbook, ANITE Productions, Pino1e, CA
Schiro, George, "Collection and Preservation of Evidence," The Texas Investigator, July/August, 1996, and September/October 1996
Schiro, George, "Using Videotape to Document Physical Evidence," The LPIA Journal, April, 1997