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Monday, December 18, 2017 MAGAZINE Volume 1, Issue 1

Gunshots to Vehicle Glass


by Michael F. LaForte

June 18, 2012

When arriving at a shooting scene where either the rear window or the door glass has been penetrated by a projectile, quick action on the part of the crime scene investigator will be required to preserve the location of the hole (Figure 1).

Figure 1

Figure 1: A bullet hole in door glass must be marked before it is destroyed.

The glass in the rear window and doors of an automobile are tempered glass and it is designed to shatter into tiny fragments from an impact, such as a projectile. If the vehicle was stationary when the bullet penetrated, the hole may be unaffected, but it will not stay that way for long. Any vibrations of the car from passing traffic, or simply opening and closing a door will cause the shattered glass to fall out, thereby losing the location of the bullet hole. Even the increase in the air temperature or an increase in the wind speed at the crime scene will cause the glass to eventually fall out.

The location of the bullet hole must be documented first, before anything else is done, even if the victim’s body is lying nearby. Take a few preliminary photographs to document the exterior of the vehicle. After the photography, it is time to mark the location of the hole.

Figure 2

Figure 2: The location of the bullet hole in the window glass has been permanently marked with the use of string and duct tape.

Using construction string, I like the bright orange or green colors, cut three lengths of string. With duct tape, attach one end of the string to the top of the door and run the string vertically across the center of the hole, anchoring the other end of the string to the opposite side of the door. Take the second piece of string and repeat the above step, except this time run the string horizontally across the center of the hole. Run the third string diagonally across the center of the hole, making sure all the strings are as tight as possible.

Now the location of the hole has been marked, and even if all the glass falls out, a bullet trajectory can still be determined (Figure 2).

Michael F. LaForte is a forensic consultant for Knox & Associates, LLC, a Jacksonville, Florida based forensic consulting company that specializes in firearms, ballistics, and crime scene reconstruction. He was a police officer/detective with the Jacksonville Sheriff’s Office for over 29 years having worked in patrol, and crime scene investigations. In addition to being a major case crime scene detective, he spent the last three years as the training coordinator for the agency’s crime scene unit. He has also provided crime scene training in Peru, and around the United States. He has testified as an expert witness in crime scene reconstruction in state courts in Florida. He has authored three books on crime scene processing and crime scene photography.