Forensics Professionals Dying for Hyperspectral Imaging

Dan Drollette

A new market may be emerging for photonics: Forensics.

Congress is considering a bill to spend $768 million over the next five years to upgrade the nation's forensics facilities; California supporters introduced their own $220 million ballot proposal to improve their state's facilities; and a branch of the US Justice Department has embarked upon a $55 million project to develop portable, photonics laboratories that could identify the genetic "fingerprints" left at a crime scene within minutes.

One reason for this flourishing interest is increased demand for DNA analysis. As genetic sequencing has become more accepted by the legal system as a means of identification, more police are routinely collecting biological samples for genetic testing. In addition, old cases are being reopened to take advantage of the new tools. The result is a huge backlog; Chicago's crime lab is 10 months behind in its testing, while New York has 16,000 rape kits awaiting analysis.

Photonics could help ease the problem, said neurologist and computer scientist Donald Malkoff. During a lecture at Photonics West, he appealed to manufacturers to develop a small, portable, mid- and far-IR hyperspectral imaging system for forensics. Malkoff estimated that a prototype would cost between $150,000 and $250,000.

He and his colleague Bill Oliver, medical examiner for the Washington-based Armed Forces Institute of Pathology, said an imaging system operating in this region could capture more detailed information than the current, near-IR hyperspectral imaging, thereby helping medical examiners to quickly and accurately ascertain the how and when of death. Pathologists could more efficiently search for evidence as tiny as a single injection site on a dead body, said Oliver, who previously acted as government pathologist in high-profile investigations such as the Rodney King assault case.

Malkoff said he became interested in the idea after his experience with the large, airborne hyperspectral cameras used by the military to gain information about the temperature, chemical composition and surface texture of distant battlefields. (The US Air Force agreed to let the pair borrow the equipment for a forensics test but later backed out.)

Based on his experience with these larger systems, Malkoff expects that this technology could tell how long a person has been dead, by determining how much the body has cooled and how far it has progressed in the sequence of chemical changes that accompany decomposition. And it could help identify the proverbial blunt instrument used in a crime by detecting any hidden patterns in skin trauma.

Technology such as Fourier transform interferometry can acquire some information, but it has drawbacks, Malkoff said. "You hold up all of a crime scene investigation while taking a single picture," he said, citing its two- to three-hour processing time.

Another potential advantage to the proposed system is its ability to chemically diagnose bodies from a distance -- important when dealing with hazardous environments or dissecting some victims of accidents and foul play. Pathologists must always beware of accidentally ingesting poison whenever they cut open a body, and cyanide is one of the most insidious of the chemical fumes outgassed, said Oliver.

"They always say it smells like bitter almonds, but who the hell knows what bitter almonds smells like?" he said.