3D Laser Scanning gives law enforcement the upper hand in crime scene investigation and recreation

In October 2011, police responded to a grisly double-murder in Rocky Face, Georgia.

An elderly gentleman and a teenage girl were found dead from gunshot wounds to the head. The scene was even more revolting because the murderer had tried to cover his tracks by setting the house on fire.

What did the Georgia Bureau of Investigation use to document this complicated crime scene? They used 3D laser scanning. According to GBI Special Agent Jerry Scott, “It’s now the best technology available for documenting and recording crime scenes.”

Collecting evidence

3D Laser Scanning is quicker than other types of crime scene documentation and the technology provides much more useful data, making crime scene reconstruction more accurate, reliable, and easier to explain to a jury.

Police generally use the Leica C-10 as their scanner of choice. This instrument can take 84 pictures in about six minutes and measure from up to 200 feet away. With this capability, crime scene documentation can take up to 80% less time.

What does is record? Well, everything.

“Where the cars were, where the debris ended up, where the body was, where the weapon was – anything seen by the scanner, we will have,” said Sgt. Jeff Davis from the Arlington, Texas Police Department to WFAA in Dallas.

3D laser scanning is increasingly finding its home in other police forces across the country.

“It has become a standard part of our initial investigation process,” said Chattanooga Police Sgt. Darrell Whitfield, who was the first Chattanooga police investigator to train with the equipment.

Lieutenant Matt Magro of the Carlsbad, California Police Department told the news in San Diego, “It allows us to recreate the scene very quickly and very accurately. You can click on the bullet hole on the wall and then go to the shell casing and it will tell you what the distance between those objects is and the elevation in just the click of a mouse.”

During the investigation

Once the site is cleaned up or altered in any way, the evidence is spoiled. However, 3D laser scanning allows investigators to return to the site at any time to retrieve missed or forgotten details. Investigators can view vivid color 3D data and extract any measurement they need long after the scene has been released.

At the crime scene, investigators take photographs, make measurements and sketches, and interview witnesses. However, even the most seasoned investigator can miss critical details due to time constraints, site access, or simple knowledge of the facts.

Sgt. Davis noted that having access to the scene as it was days, months, or even years after is extremely valuable. “If something comes up later, then we are able to go back to the scan and extract that information.”

As a case develops, investigators can use the 3D scan to determine which “witnesses” could really see what happened. When a gun is involved, for example, built-in shooting reconstruction tools can zero in on probable shooter locations.

Using the data at trial

3D laser scanning has also become a game-changer in court.

“It gives juries a virtual tour of the crime scene,” said Iredell County, North Carolina Sheriff’s Chief Deputy Rick Dowdle in the Moorsville Tribune.

Traditionally, the jury is shown a series of photographs and two dimensional diagrams of the scene. This requires a great deal of explanation and imagination on the part of the jury.

It is also an answer to what Hamilton County District Attorney Bill Cox calls the “‘CSI effect” among modern jurors, many of whom consume a steady diet of crime and courtroom dramas.

“People watch television and they expect a lot of high-tech video and audio evidence,” Cox said in a recent interview.

As noted by Lt. Warren Hamlin of the Knox County Tennessee Police Department in an interview related to a murder trial in Tennessee, “It’s almost like taking the jury right to the crime scene. We can show pictures all day long, but when you’ve got a panoramic view that shows exactly how it looked and where everything was, that’s a much better depiction than a photograph. So, if a guy says, ‘I was standing in that corner,’ you can create a viewpoint exactly where his head would be and look around the model and tell whether yes, he could see that, or, no, he’s lying.”

The truth is that law enforcement is developing a tool to cut its investigation time and dramatically improve its effectiveness both during the investigation and in court. Defense attorneys had better start catching up.


David Headrick has over 20 years of experience in the surveying, engineering and legal industries, both as a project manager for LandAir Surveying and as a lawyer in private practice. He has represented numerous land surveyors, designers, architects, contractors and other industry professionals throughout his career. Today, David serves as an executive and project manager for LandAir, focused on developing and managing the company’s 3D Laser Scanning department. Contact him at


Double murder victims shot in the head before suspect set house on fire (located at

Georgia Bureau of Investigation agents train with 3-D laser scanners in Dalton (located at

High-tech scanning system keeps record of scenes for Arlington PD (located at–Scanning-Incidents-in-Arlington–171642511.html)

Laser scanning system enables CPD to reproduce 3D crime scene (

Revolutionizing Crime Documenting Tool (located at

An armed robbery, a high speed police chase and…laser scanning?

Sometimes I don’t have to look past the front page of the local newspaper to see a good example of laser scanning in action.

Tragically, there was a police-involved shooting in Cobb County, Georgia, this past weekend, as reported by the Atlanta Journal-Constitution. The suspect allegedly robbed a gas station and then led the police on a high speed chase. The chase ended on I-75 when the suspect pointed a weapon at the police officers and was shot dead.

This was a very unfortunate incident, but the impact on the community was far lessoned due to the outstanding work of the Georgia Bureau of Investigation.

The shooting and subsequent chase left many cars wrecked and damaged and, ultimately, the interstate was forced to close temporarily. As you can imagine, this was not a calm situation.

The GBI dispatched their laser scanning team to the site to set-up and scan the area to document the evidence both known and unknown at the time. They also generated 3D photography to further document the area in its entirety.

Using this method, they not only saved time, but were also able to quickly collect the data that would be necessary if the case were to go to trial.

So why use laser scanning to document a scene like this?

First, consider the sheer size of the scene. In this case, the area of study was larger than a football field. Without scanning, investigators would have had to take multiple photographs and make measurements with total stations that shoot one point at a time or worse, measure with 100 foot-long measuring tapes.

This takes much more time, requires more people, and creates much more chance for errors. The errors could be wrong measurements or even missed objects.

When you combine the laser point cloud data with the photographic data, the measurements and the scene become much more intuitive and obvious. You can place the evidence markers by the evidence within the scene and the scanner automatically picks them up.

Instead of making and recording many different angles and distances, you simple put in the points per square foot you want to capture into the scanner and in about 15 minutes, you have a completed scan with photography.

You can look at the scan and very clearly see the markers and measure from any object in the scan to any other object in the scan. So, if you need to know how long a skid mark is, for example, you would just click two points – one at the beginning and one at the end – and the measurement would be instantly generated.

With laser scanning, time at the scene is used to locate and mark the evidence and important points in the scene. All critical measurements can be made offsite after the scene is moved and the traffic is moving again.

Here’s the most important part: If you need information about the scene, but did not know it at the time of the scan, all is not lost! If it exists in the scan, you can make all the measurements you need to document the new (previously unknown) evidence.

More and more, laser scanners are being used to document crime scenes across the country. District attorneys like the scanned data because they can easily view it.

Scanned data is totally objective in that it collects the whole scene. It is easy to put a point down on the ground every square inch so that the coverage of the site is complete. Additionally, the fact that no one has to decide what measurements are made in the field before they release traffic is very important.

Judges like the data because the jury does not have to visit the site to understand the scene. Instead, they can simply view it in 3D on a computer screen without leaving the courtroom.

Laser scanning also saves time and money. Traffic still has to be stopped for an investigation, but if not for laser scanners, it would be stopped longer and there would be less information collected.


Tate Jones has over 40 years of experience in land and aerial surveying and was one of the country’s earliest adopters of 3D laser scanning technology. A nationally recognized expert in the field of 3D data capture, he has worked with hundreds of clients in the forensic engineering, law enforcement, criminal defense, architectural and construction industries. Contact him at, a division of the LandAir Surveying company.