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The newest advance in clandestine grave detection may come from a handheld device, not from the next generation of human remains detection dogs.
Dead men do tell tales. A new hand-held odor-sniffing technology capable of locating buried human bodies has emerged at Oak Ridge National Laboratory in the form of a device called LABRADOR, an acronym for Light-weight Analyzer for Buried Remains And Decomposition Odor Recognition.
The instrument is designed to be used at the soil surface to detect volatile organic chemical compounds (VOCs) emitted by decomposing human bodies buried in shallow graves 1.5 feet to 3.5 feet deep. According to the FBI, the average clandestine grave is about 2 to 2.5 feet deep. In the case of a corpse buried in roughly 18 inches of soil, it takes about 17 days for odors to first make their way to the surface.
The Oak Ridge device is not as sensitive as innate canine olfactory capabilities, but one advantage of LABRADOR is that it can detect and alert the operator to the amount of odor present.
“In other words, it can map the odor plume coming from the ground where the body is buried, which can be a key factor in pinpointing the location of the grave or looking for victims in natural disasters,” said Oak Ridge senior researcher and forensic expert Arpad A. Vass, leader of the team that developed LABRADOR. Vass is also affiliated with the University of Tennessee’s Anthropological Research Facility, known also as the Body Farm, a research lab devoted to studying the decay of donated human remains over time in various environments and conditions.
Police frequently use dogs trained to detect the odor of human decomposition to help find clandestine burials. However, few studies have attempted to identify the specific VOCs emitted from decaying corpses. Vass decided to find out what chemicals reach the surface that originate in a buried human body.
He started by collecting the VOCs associated with burial decomposition—those that rose through the soil and reached the surface. Triple sorbent traps were used over four bodies for four years at the Body Farm to collect air samples. Eight major classes of chemicals were revealed which now contain 478 specific volatile compounds associated with burial decomposition.
Samples were analyzed using gas chromatography-mass spectrometry (GC-MS), and were collected above and below the body in order to assess any changes in chemical concentration that occurred during migration to the surface. Of these 478 compounds, 30 were identified as key markers of human decomposition that are detectable at the soil surface by either analytical equipment or human remains detection dogs, including 12 of 72 compounds emitted from bone in the absence of any tissue.
Some of the more interesting and unique chemicals Vass identified are fluorinated compounds.
“We identified fluorinated compounds coming out as vapors from buried bodies,” Vass said. Vass believes this is because Americans drink fluorinated water and that it may be possible that, as bodies decompose, fluorine combines with hydrocarbon compounds, generating a distinct detectable compound.
The VOC program, funded by the FBI, began in 2002. The spin-off LABRADOR project began in 2007 and is funded by the National Institute of Justice. The VOC database was first intended to identify the odor signature unique to human burial decomposition and to use this information to improve cadaver dog training. Cadaver dogs are believed to be able to find human remains even hundreds of years old and can also differentiate human bones from animal bones, useful information for forensic investigators attempting to determine if a bone in question belonged to a baby or a chicken.
However, cadaver dogs are difficult to train, can be expensive to maintain, and are not always available when needed.
Vass believed if he could develop a detector that could mimic what cadaver dogs do so well, the cost to law enforcement could be significantly reduced. Once LABRADOR is obtained by a police agency, it would be available at any time on short notice, would never have to eat or rest, and wouldn’t need a trainer or a kennel.
Vass said that LABRADOR was constructed with common, off-the-shelf components where possible to minimize costs and has specific sensors designed to detect many of the chemical compounds peculiar to human decomposition. It is self-contained, portable, and built for field use. A data port allows the operator to download data when desired.
“Currently, we are seeking a patent on this novel detector and hope to find an industrial partner willing to manufacture this instrument once the patent process is complete,” Vass told Forensic Magazine.
During the patent process, Vass is not at liberty to discuss the exact sniff sensor technology used by LABRADOR. He did speculate that the total cost per unit would likely be in the $1,000-$1,500 range once the device is placed in production. The instrument runs on batteries that last up to six hours in continual operation.
“While not as sensitive as a mass spectrometer, tests have shown that in less than 60 seconds LABRADOR can provide qualitative data comparable to what is seen with GC-MS headspace analysis with collected field soil samples,” Vass said.
Potential applications for LABRADOR go beyond detection of clandestine graves. The technology can also be used in any law enforcement endeavor where odor can be liberated from a target, such as locating and identifying accelerants used in arsons, detecting concealed explosives, and finding the exact location of illegal methamphetamine labs.
“Odors generated from the process of making meth or chemicals used in the process are easily detected using sniffer technology,” Vass said.
LABRADOR also has several potential military applications, most of which cannot be divulged.
“The one I can discuss is finding graves of service personnel who have been killed overseas,” Vass said.
Vass said it might also be possible one day to integrate LABRADOR with robotic rovers to keep personnel and canines out of dangerous situations.
Meanwhile, the device continues to be improved. There are issues with possible environmental interferents that need to be resolved, and Vass is also looking at additional volatile matrices to expand the instrument’s sensitivity.
Douglas Page writes about forensic science and medicine from Pine Mountain, California. He can be reached at firstname.lastname@example.org.