Freeze it while it’s hot!

Insights from a fire and explosions visualisation expert.

Expert Insight Fire Investigation Jason Mellstroem

Forensic photographer, and crime and fire scene visualisation expert, Jason Mellström shares his passion for the unique technical and procedural challenges of fire scene investigations.  

Born into a family of photographers, Jason Mellström has a passion for the perfect image in his DNA. “But normal photography quickly hits its limits on a crime or fire scene because everything is black. So how do you get a meaningful image?” That’s the question that Jason was asking at the National Forensics Centre in Sweden when he began contributing to the development of 3D technology for forensic documentation. 

Fire and Explosion Investigation - Forensic Photography - Jason Mellström

Jason Mellström, Business Developmen Manager Public Safety Nordics - Leica Geosystems

“When I first got my hands on the Leica RT360 technology package, it reminded me of getting my first EOS digital camera and Photoshop; a whole new world opened to me. Suddenly I could work seamlessly and tell visual stories in completely new ways. The RT360 laser scanner is a similar thrilling discovery. It allows you to combine point cloud data and photographic images and other data to visualise and reconstruct the stories of fires or explosions and then share them with stakeholders in a seamless workflow” explains Jason.  

Carbon clues

“In fire and explosion investigations we have a variety of clues. For example, which side of a doorpost is burnt darker? That tells you which direction the fire was going. Or what color is the melted metal? That tells you the fire temperature. There are also phenomena like heat shielding or debris patterns that contain important information. During fires you often get things collapsing and during explosions there are a lot of scattered parts. Often these objects are blocking access to crucial evidence that the investigator needs to examine. And they are carbonized, meaning they break when you touch or tread on them. That is why you need to be very careful in the way you approach the scene.” explains the veteran investigator.

Leica RTC360 in fire investigation

Leica Geosystems RTC360 laser scanner during a fire investigation


“To secure the vulnerable evidence, you need to freeze the location as soon as possible after the fire – while it is still ‘hot’. The goal is to preserve the scene as accurately as possible during the first walk-through in a Forensic Digital Twin. This is a 3D real-time virtual representation of a physical location. Once you have captured the scene data in this way, you can start shifting things to see what’s behind or underneath. Leica Geosystems’ fire investigation solutions are a response to all these challenges,” says Jason Mellström with conviction.

         Leica Public Safety fire investigation with the RTC360_fire scene


Comprehensive data with no compromises

Firstly, with the RTC360, you can work quickly without having to compromise on resolution. You can document and visualise the location with high-quality 3D scans at a rate of up to 2 million points per second. That allows you to capture 3D color point clouds in under 2 minutes. Secondly, it is comprehensive: the field of view is a generous 360° horizontal and 300° vertical field and you can attach additional information like images, text or geodata to the scans. Thirdly, you don’t have to worry about the light: you can scan in pitch darkness and still get accurate results as the RTC360’s Class 1 laser works with 1550 nm light that is invisible to the human eye.

For field operations, a light, compact and robust system are also very important factors. The RTC60 is IP54 rated for dust and water protection and can be paired with a dedicated lightweight tripod to offer a highly portable and versatile system. A single user can carry it from setup to setup and access tight spots as needed – all day long and without fatigue. This is a huge advantage because the less people are involved, the easier it is to avoid disturbing the fragile post-fire scene evidence.

During the rescue or cleanup phases, response team safety is also an important topic. But Leica has that covered too. The fire brigade can monitor the structural stability of the burnt building using a Leica Total Station. If the structure starts to move, the device gives visual feedback right away and sounds an alarm. This allows the commander to order an immediate evacuation before anyone gets hurt.

All these features allow investigators to work effectively and leave the site confident that they have all the necessary data. After all, for most fire or explosion investigations, returning to the site just because someone missed an important piece of evidence is not an option.

Seamless sharing with stakeholders

All fire investigations start with the work of the fire brigade. If someone was hurt or there is a suspicion of arson or fraud, then the police get involved. Otherwise, it is usually private investigators working on behalf of insurance companies. For example, the investigation could be about looking at the remains to see if the value of the claim is plausible. Or it could be about finding the origin of the fire to determine if negligence or an accident was the reason for the fire.

The best way to expedite the investigation is if the investigators have a seamless 3D documentation and visualisation solution. Then you can create a Forensic Digital Twin and allow all the stakeholders to immersively explore an immutable record of the original scene. Ultimately it helps them to make solid, informed decisions.

“Being involved in the development and sharing of new technologies with the Public Safety community and customers around the world really motivates me” explains Jason who now works for Leica Geosystems as a forensic and visualisation expert.

“The technological development over the past few years has made laser scanners faster, more accurate and easier to use, making scanning data acquisition in the field more efficient and more fun than ever before. The RTC360 offers a combination of hi-precision, accuracy and robust reliability under a wide variety of conditions. There is nothing like it.”

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3 good reasons to choose the Leica RT360 laser scanner

The Forensic Digital Twin created on a fire scene allows investigating parties to do as many virtual site walk-throughs as they want, looking at the scene and evidence from different angles.

The resolution of a Digital Forensic Twin data created by the Leica RT360 laser scanner allows the investigator to capture and retain important information about the scene that can be important in reconstructing the story of the fire decisively. 

Leica Geosystems fire and explosion investigation technology can also be used to monitor structural stability during the rescue, inspection, or clear-up phases thus protecting lives. 


Forensic Expert: Jason Mellström 
Segment Manager - Public Safety & Forensics - Nordics
Leica Geosystems

Author: David M. Taylor

Editor: Malgorzata Krol
Senior Manager - Public Safety & Forensics
Hexagon Geosystems

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