Why 3D Laser Scanning Is Invaluable in Shooting Incident Reconstructions
Michael Haag, a private consultant and a forensic scientist with a major southwestern law enforcement agency, has been using Leica 3D laser scanning technology for nearly a decade for shooting incident reconstructions. An expert in firearms and ballistics, Haag has been involved in some very interesting cases, including the recent reconstruction of ballistic evidence from the 1963 assassination of President John F. Kennedy for the NOVA documentary on PBS, “Cold Case JFK.”
For Haag, the ability to create an accurate three dimensional representation of the scene is invaluable. “It’s critical in [answering questions in] an investigation,” he says.
Accurate and Traceable Evidence
The 3D laser scanner can document the precise location of the firearm and the primary point of impact, as well as any secondary impacts downrange. This data allows for a very accurate determination of the deflection of the projectile, Haag says. Tools within Leica’s Cyclone software are then used to create a line segment for the original trajectory and any secondary trajectories. The use of Leica Geosystems NIST traceable twin target poles establishes that the scans are accurate and to scale.
For the NOVA documentary, Haag traveled to Dealey Plaza, the location of the JFK assassination, where he was joined by Tony Grissim of Leica Geosystems, a technical advisor for the Association of Firearm and Tool Mark Examiners. Using a Leica ScanStation, the team spent an entire day collecting laser scan data from the plaza and from inside the Texas School Book Depository (now known as The Sixth Floor Museum at Dealey Plaza) where the shooting is said to have taken place. The use of laser scanning, along with other high tech equipment such as Doppler radar and high speed videograph made the investigation unique and provided a new level of information that wasn’t available to investigators 50 years ago.
“When I want to look at some new hypothesis or some new conspiracy theory about what happened, I don’t have to go back to the scene; I can just go to my computer and start clicking on scan data to look at distances and angles, and start to compare those points and angles to what I know occurred ballistically,” Haag says. “A lot of the conspiracy theories that people throw out there really haven’t been tested with the physical parameters of the scene. They just throw these ideas out there and hope someone will believe in them. With the scan data, once you go in and start either putting yourself in a particular viewpoint or extracting these measurements, it’s pretty easy to begin knocking some of those theories down … or see what is possible.”
A Primary Crime Scene Investigation Technology
Haag, whose book Shooting Incident Reconstruction (Academic Press, 2 ed., July 13, 2011) is considered the last word on the subject, teaches a three-day shooting scene reconstruction course through his company, Forensic Science Consultants LLC. He has recently begun offering an optional fourth day focused on 3D laser scanning. “I started asking agencies whether they would be interested in that add-on session, and that has really skyrocketed,” he says, noting that classes are beginning to sell out several months in advance.
“In the crime scene investigator community, Leica 3D laser scanning is well on its way to becoming a main staple,” he says. “The number of scanners that are out there and the number of agencies that are operating them has been increasing every year. The technology is here to stay.”
Note: “Cold Case JFK”is part of series of specials airing on PBS Nov. 13, 2013, to commemorate the 50th anniversary of President John F. Kennedy’s death. Watch the preview here.