An Easy Way to Preserve Evidence in Fire and Explosion Investigations

Forensic investigators are challenged not only with the complexity and devastation that result from fire and explosion incidents but also with the imminent threat of the bulldozer demolishing the scene. This is one reason why Dr. John DeHaan, president of fire and explosion consultancy firm Fire-Ex Forensics Inc., has been advocating for the use of laser scanner technology in this field of forensics for more than five years. The high-definition 3D laser scanner allows first responders to quickly, comprehensively and accurately capture the scene—and the evidence it contains—before it is lost forever. “Being able to capture all of the distance and visual data in just a few minutes is irreplaceable,” DeHaan said.
a photo of an explosion sceneThe Challenges of Premature Scene Demolition
In fire and explosion incidents, the arrival of the bulldozer may be inevitable and even advisable for body recovery or public safety concerns. However, DeHaan has seen demolition take place too hastily. “You get cities that are bulldozing fire scenes because some lawyer has convinced them that it’s an attractive nuisance, that people could get in there and get injured and we [the city] could get sued,” DeHaan said. “They’ve taken that to ridiculous extremes.”
In Ohio, a house fire in 2000 killed two children. Demolition began the same day the insurance investigators were on site. “They chased the insurance investigators out, literally, with the bulldozer,” DeHaan said. “And that was two days after a multiple-fatality fire.”In Rhode Island, The Station nightclub was demolished hours after the tragic 2003 fire killed 100 people and injured more than 200. “I was involved in that fire [investigation],” DeHaan said, “and the recovery people leveled the building by the first morning. There was literally one wall standing.”
In Connecticut, a 2012 house fired killed four occupants. “There was minimal investigation done,” DeHaan said, “and they came in the next day and bulldozed the building.”
In cases such as these, the bulldozer isn’t merely demolishing the structure. It’s destroying evidence needed to determine not only the cause of the fire but also whether the fire could have been deliberate. “So now when the investigators are asking, ‘Could it have been this? Could it have been that?’” DeHaan said, “we don’t know. We will never know.”
The Answers Are in the Scans
A fire or explosion site captured with a high-definition 3D laser scanner, in contrast, is always available for further investigation and analysis. State-of-the-art 3D point cloud processing and visualization software transforms millions of data points into a virtual model of the scene exactly as it was at the time of capture. Even after the physical sight has been demolished, investigators can examine the pristine scene whenever the need arises—be it days or decades afterward.
“If we get that kind of scan properly done, then it doesn’t matter quite as much. We can still reconstruct the building. We can look at fire dynamics. If it’s an explosion or a collapse or whatever, we can test various hypotheses,” DeHaan said. “So it’s a tremendous advantage over just some pictures or some hand-drawn diagrams.”
For more information on 3D laser scanning technology, contact us.
About the author: Wendy Lyons is journalist living in Canton, Georgia, who spent several years writing about surveying technology for POB magazine. She now focuses on covering laser scanning and other geospatial measurement solutions for public safety professionals.

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