Science has discovered another cutting-edge way to enhance criminal investigations. A groundbreaking study reveals that a person’s hand odor can determine if they are – a “man or woman.” This means police investigators can have forensic lab specialists test an object left behind by a perpetrator(s) and the odor emanating from the object may discern if the odor may belong to a male or female and also reveal the sexual identity of the person, according to Florida International University, earlier this month.
Sounds incredible, doesn’t it?
Although a canine dog can identify human scent, living or deceased, this hand odor discovery is one of the first times a person’s odor has been analyzed in the laboratory to accurately determine the person’s sexual identity.
For example, violent crimes like robberies, rape, assault, and kilos of dope, crimes involving touching can be linked based on a person’s hand. By using the hand odor technique, police authorities may be able to track down the perpetrators and predict their sexual identity.
How Does it Work?
The test reveals how the continual shedding of the epidermis of the skin is primarily responsible for human body odor, which is a complex mixture of volatile organic compounds (VOCs) released by the body. Dogs have long relied on these volatile organic compounds (VOCs) for the accurate identification and tracking of individual humans.
However, things change drastically in the laboratory.
Researchers from Florida International University found that the person identified by the odor profile in the lab has proven challenging due to a lack of comprehensive datasets and well-developed analysis methodologies.
The team behind a new “PLoS ONE” study aimed to advance this inquiry by providing empirical evidence for the usefulness of VOC profiles in sex discrimination, comparison, and classification. Though additional work is required, their analytic procedure/model correctly identified female and male respondents based on hand odor 96.67% of the time.
“Within forensic science, we’ve used human scent for matching people to sort of individualize them, and in this case, you could use it for class characterization,” Executive Director of the Global Forensic and Justice Center (GFJC), Dr. Kenneth Furton told NBC6. “That means if you could collect a scent sample you can determine whether a male or a female potentially committed a crime and use that for an investigative tool.”
GFJC has one of America’s oldest forensic science education programs and has grown into one of the world’s largest forensic science centers.
According to FBI figures, about 72% of crimes are committed by men and about 28% by women. The research also could lead to non-forensic applications in the future.
The current study relies on a foundational principle in forensic science – every contact leaves a trace. When a suspect touches something, they leave something behind, including their odor.
“Let’s just say I have a mug here, and I touch it. My human scent is on the mug and you could collect that scent. Later on. if you have the ability to match it to somebody, you could do that or if you don’t, you could take that scent and say, well, that scent actually came from a male who was a particular age and a particular race, and you could use it for investigative purposes,” Furton said.
“There’s still more work to be done, but the results we found, which were over 96% accurate in differentiating males and females, give us one more tool for investigative purposes,” Furton said.
Furton Testified As An Expert in Casey Anthony’s Trial
As a professor of chemistry, Dr. Kenneth Furton played a pivotal role as a defense witness in the sensational trial of Casey Anthony. Furton studies the chemistry of human decomposition and the scent of human remains and was accepted as a forensic chemistry expert, reports CBS affiliate WKMG.
Furton claimed that a prosecution witness’ method for determining human decomposition was flawed. He testified that many of the compounds recovered in the trash of Anthony’s trunk are the same that Dr. Arpad Vass is relying on to claim that there was a decomposing body in the trunk, the Florida TV station reported at the time.
Dr Vass previously testified that air samples taken from the trunk of Anthony’s car indicate human decomposition had taken place. He also said there was an unusually high level of chloroform in the air sample.
Furton debunked Vass’ conclusion.
“It’s my expert opinion that there’s currently no instrumental method that has been scientifically validated to the level that it could be used to identify the presence or absence of human decomposition,” Furton said, according to the station.
The nation recoiled in outrage when a jury declared Casey Anthony “not guilty” in the death of her three-year-old child Caylee Anthony.
Roughly 97% Accurate
Thirty males and thirty women, ranging in age from 18 to 46, of African American, Hispanic, and Caucasian backgrounds provided samples for the study. The volunteers had to wait an entire hour after washing their hands to participate in the sample. Scientists collected samples from willing participants by having the participants squeeze sterile gauze pads for 10 minutes.
Three Hand Odor Analysis Models
Initial analysis of the hand odor samples was performed by the FIU group using headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Following this, the correctness of the VOC data was assessed using three distinct data models: partial least squares discriminant analysis, orthogonal projections to latent structures discriminant analysis, and linear discriminant analysis.
Two Models Failed
The study found that there was not much of a difference between the sexes and that two of the models (PLS-DA and OPLS-DA) revealed clustering among the male and female subjects.
One Successful Model
The LDA, on the other hand, accurately predicted and discriminated samples based on whether they were from male or female donors 96.67 percent of the time. Two samples, one male and one female, were incorrectly categorized by the model. The researchers speculate that the overabundance of chemicals matching the profiles of male subjects could account for the misclassification of the two samples.
The findings of this study may have far-reaching implications for the forensic use of human odor. Researchers can now “rapidly assess the volatiles of collecting human odor samples,” as they put it in their report.
There is, of course, always room for development. The length of time it took to analyze the data was cited as one of the study’s major flaws by the FIU team.
To reduce the likelihood of missing potentially useful molecules that would take longer to elute, forensic researchers employed a thorough approach that included extended extraction and GC/MS run times.
This prolonged the total time required for the HS-SPME-GC-MS analysis, which may be a drawback. The study’s results suggest, however, that the approach may be modified to shorten the time required to analyze the data collected.
The scientists also couldn’t use machine learning or deep neural networks since the study’s sample size was too tiny. However, with sufficient depth in the sample data, natural language models like that may offer hope.
Hand Odor Model Potential Future Application
Although the researchers focused on age and race in this study, they note that the overall statistical methodology they used may be applied to other identification criteria in situations when other discriminating data may be missing.
When applied to different forensic data sets, the models pave the way for a tool that can make systematic comparisons of volatile organic compounds, as the study’s principal author, Chantrell Frazier, put it. The use of detecting dogs is another viable option. It’s another tool that can help investigators bring justice to crime victims.
News Reporter Clarence Walker can be reached at [email protected]