"Now it made sense, the investigators were able to see what had happened," said Long, adding that because the case is still ongoing he can't provide further details.

Keeping the Scene Clean

A basic concept taught to first responders is securing a crime scene, so contamination of evidence is minimized.

Crime-scene contamination can take many forms -- someone may touch an object leaving their fingerprints, or inadvertently move or take evidence from the scene, perhaps by picking up fibers on their shoes.

Analyzing a scene's evidence helps explain what happened, and if an item of evidence is moved or disturbed from its resting place, the analysis could be faulty.

The time after a crime has been committed, during which there is a maximum potential for the recovery of forensic evidence, is referred to as "the golden hour" by Mark Harrison, MBE, special adviser to the UK's National Crime & Operations Faculty (NCOF).

Harrison, an 18-year veteran of British policing, is on loan from the Bedfordshire Police to the NCOF, a national organization in the UK that provides special services during complex investigations.

He commonly uses HDS technology as a "stand off" device, allowing him to approach the scene in stages by scanning from the outer perimeter and moving into the heart of the scene.

"The laser doesn't care if its day or night," Harrison said. "It captures the information and allows me to interrogate the crime scene with my laptop before it has been disturbed."

In the past, the method of preserving information about the evidence was photographic documentation and two-dimensional drawings. Later, not only could someone testify to the recovery of the evidence, they might also provide expert interpretation. Drawings and photographs assist investigators in the investigation, and ultimately assist prosecutors in telling the story to a jury.

In many cases, Harrison said, the value of evidence is in its positional relationship.

"It could be blood splatters, a firearm, shell casings or any other pieces of physical evidence," he said.

Investigators often go to elaborate means to reconstruct scenes. Unfortunately no matter how good your photographer, there is always something else an investigator wants to know. Photographs and drawings are helpful, but they are two-dimensional, and are the technician's interpretation of the scene.

Long and Harrison agree that observer bias always creeps into photography and crime-scene drawing. If an HDS device is used at the scene, detectives, prosecutors and juries can return to a crime scene in its preserved state.

Matter of Perspective

The investigative and prosecutorial value of virtual crime scenes is evident. Showing a jury exactly what a witness could or could not have seen can be very valuable.

Recently Craig Fries, president and founder of Precision Simulation, said his company was asked to re-create an officer-involved shooting in the San Francisco area that occurred one year earlier.

There were more than 40 witnesses to the incident, he said, and the scene itself was approximately 400 feet by 2,000 feet -- an entire city block with businesses and apartments. Using HDS technology, Fries scanned the scene, the involved vehicles (at the impound yard) and used photographic evidence to reconstruct a virtual model of the incident that could be examined from almost any point of view.

"Once the plaintiff knew what we were able to provide, they dropped the lawsuit," Fries said, adding that HDS technology is beginning to be a tool used by both the defendant and plaintiff. "If done well, it's very compelling to the jury."

HDS works equally well in a large rural area. Harrison recalled a political execution in Ireland where the crime scene was a large pasture. HDS technology allowed investigators to document the entire

Lt. Raymond E. Foster  |  Contributing Writer